Because LEGO put all their eggs in one basket, and it’s what they’re known for.

Back in the 1930s, 40s, and 50s, LEGO made a lot of different types of toys. They weren’t a construction toy company— they were a toy company. They made wooden toys and plastic toys. They had toy guns, toy cars, baby rattles— they even made a board game.

(One of LEGO’s successful plastic toys, the Ferguson tractor)

They started making the plastic building bricks in 1949, calling them “Automatic Binding Bricks”. If you stepped on one back in 1949, you wouldn’t say “Ow! I stepped on a LEGO!” anymore than you’d say “Ow! I stepped on a Mattel!” It would just seem silly.

In the mid 1950s, LEGO really started putting its weight behind the plastic bricks. It also started calling them “LEGO Mursten” (which means “brick” in German).

LEGO still made other products, but the plastic bricks were quickly becoming the flagship product of the company.

Then, in 1960, LEGO had a fire at the company. It burned down the majority of the wooden toy division. They had the choice to rebuild it, or to just focus on their plastic building bricks.

There was quite a dispute, actually, since it was a family-owned business, and there were differing opinions on the matter. Godtfred Kirk Christiansen (son of the company’s founder, and head of the company at the time) decided to focus solely on the plastic bricks. He bought out his siblings’ shares in the company, and some of them went on to found “Bilofix”, which continued to make wooden toys.

From then on, LEGO became known for pretty much their only product, which was the plastic building bricks. And they dropped the title “Mursten”— making “LEGO” seem a lot less like the brand name, and a lot more like the actual product itself.

Hence, now people say things like “a piece of LEGO” or “a pile of LEGOs” or “lots of LEGO”, or even “a LEGO”, rather than always qualifying it with the more proper “LEGO elements” or “LEGO brick”.

One quirk seems to be that in the English speaking world, the United States (for whatever cultural reasons) tends to be the main place where people say “LEGOs” as the plural rather than “LEGO” as the plural. The LEGO company even asked (back in the 1970s and 1980s) people not to use the term “LEGOs”, but it didn’t do much, other than to make certain rabid fans recoil in horror whenever they hear the term.

I suspect that the same may be true for the singular “a LEGO” as well— IE, terminology mostly used within the US as opposed to elsewhere. This is likely due to Americans viewing LEGO elements largely the same way (noun-wise) as, say, “picture frame”. You’d say “a pile of picture frames”, or “a picture frame”. However, elsewhere in the world, it’s more akin to “sand”, where you’d say “a pile of sand” rather than “a pile of sands”— and similarly “a piece of sand” rather than “a sand”.

So if you want to avoid critique from nasty rules lawyers and fanatical hobbyists, you should probably just say “LEGO bricks” or “LEGO elements”. And it’s doubtful that anyone will correct you if you say “LEGO” (as the plural) or “a piece of LEGO”, even though that’s not quite the preferred term. But go around saying “a LEGO” or “LEGOs”, and you’ll eventually get yourself corrected by some persnickety folks.

Why? The analysis is elementary: it is widely known that, in addition to starving the world’s widows and orphans, fomenting war around the globe, and causing natural disasters that threaten all human life, all Americans are ignorant of anything that does not originate in the United States. In their arrogance, they ruthlessly employ the brand name as a noun, and in their cultural blindness, thus grievously offend the owners of Lego, and the peace loving Danish people, by omitting the word “brick” when describing the sublime product.

A motion will be filed in the International Court of Justice demanding an abject apology from the citizens of the oppressive hegemon, and imposing severe tariffs on their future purchase of plastic bricks.

As a British person who has studied mathematics (and continues to do so) I’m on the side of the Americans here.

I’m not saying that Americans are right to say “math”, nor am I saying that they are wrong. It sounds odd to my British ear when I hear it because it’s not what I grew up with, just as Americans might find my own casual unthinking use of “maths” strange and intrusive. I am saying that its an informal abbreviation and it’s silly to get worked up about it. I know what they mean and they know what I mean and that’s all that matters.

If we were being (heaven forbid!) pedantic about it, it’s the Americans who are probably strictly correct here. Math is a singular form because mathematics is singular, just as ethics, metaphysics and all the other things Aristotle concerned himself with are singular because they are individual disciplines within Aristotle’s field of philosophy, And we say philosophy, not philosophies even though philosophy, like mathematics, encompasses a variety of individual disciplines. As part of my mathematical studies I studied statistics, which wasn’t in Aristotle but is a coinage formed as if it were. I call it ‘stats’ in short, I assume Americans would contract it to ‘stat’ but I really don’t know.

Just because an English word ends in an s doesn’t necessarily make it plural although many assume otherwise and it’s one way in which formal language changes through unwitting popular usage. The round green vegetable that comes in a pod was once a peas; one peas, many pease (which is how pease pudding came about) and now it’s one pea, many peas . There was a fitness instructor in my neighbourhood once who drove around in a car with the vanity plate B 1 CEP and I used to roll my eyes since the muscle in your arm is a biceps and it is invariant in the plural. My favourite is ‘suburbs’, which was a singular noun unchanged from the Latin; it means “the under city”, the red light district, and the good people of Hampstead Garden Suburb would no doubt be mortified if this were more widely known. Mistress Overdone in Measure for Measure kept a bawdy house in the suburbs.

This question is formulated incorrectly. To have a plural you must first have a singular. E.g. The word "Oranges" is the plural of the singular "Orange". For some items the singular and plural are the same word. E.g. The plural "Sheep" for singular "Sheep".

But *neither* form applies to LEGO because there is no such thing as a singular "LEGO" that requires a plural, either "LEGOs" (like oranges) or even "LEGO" (like sheep).

There is no such thing as "a LEGO" that requires a plural. Many Americans mistakenly refer to a LEGO piece as "a LEGO" but this is incorrect. It is a LEGO piece, or a LEGO brick or a LEGO element.

LEGO is supposed to be used as an adjective, not a noun, unless referring to the brand/company itself as a whole. So the plural of "LEGO brick" is "LEGO bricks".

A LEGO brick > some LEGO bricks, or simply, some bricks.
A LEGO piece > many LEGO pieces, or simply, many pieces.
One LEGO set > two LEGO sets, or simply, two sets.
The LEGO element > the LEGO elements, or simply, the elements.
A LEGO minifigure > an army of LEGO minifigures, or simply, an army of minifigures.

An explanation of this issue and the correct usage used to be printed in American LEGO catalogs. The USA is about the only country where people incorrectly use this terminology of "a LEGO, many LEGOs". The LEGO Group (the company) do not approve of this terminology.

The worst example of this is when I saw a person refer to a LEGO minifigure as "a LEGO". I forget the exact situation but they said something like "He put a LEGO in the toy car" when someone had put a LEGO minifigure in a non-LEGO toy car.

Many people across the world also refer to every LEGO piece as a "brick" even though most elements are not bricks but instead are plates, wheels, doors, minifigures, etc. Bricks are just one type of piece, the actual brick-like blocks.

We treat the word “math” like the Brits treat the word “sport” as in, “Do you do sport?” as opposed to, “Do you play sports?” While it's obvious that Formula One and Cricket are separate sports, Brits regard engaging in sport as a singular body of activity: physical exertion combined with competition. It's a generic and easily accepted quirk of the language.

Americans do the same with “math/s”. Sure, Trigonometry and Calculus are separate maths, but just as Cricket and Formula One Racing are referred to collectively as “sport”, these two studies along with all the other types of math, are commonly referred to as math.

This is annoying to some Brits, but it's not so difficult to understand.

There are no clearcut rules to abbreviations. If there were, the abbreviation of pound certainly wouldn’t be lb. Yes, I know it comes from Latin libra, why didn’t it come from pound? Why do both Americans and Brits ignore the “ematic” which is also obvious? Because they both are shortening the word. American and British English began bifurcating in 1776 when governance did, and we shorten the word in different ways. (Brits might say 1783, when they finally admitted to our independence.)

On the other hand LEGO® is not an abbreviation, it is the registered name of a company, its products, and, at least in the US, also a reference to the individual blocks which make up its product. When referring to multiple blocks, Legos seems rather obvious and shorter than saying “LEGO® blocks.”

OK, Brits originally developed the language. I understand you get more upset about Americanisms than we get about Briticisms. However, the mother languages of all former colonial powers have tended toward independent change in their former colonies. “You do you, we’ll do us, thanks.”

Short answer: ignorance and adoption of the vernacular.

Long answer: Most people in the United States (and probably around the world) pluralize the brand name “LEGO” using their language’s rules for creating plural nouns without thinking about if there is a special case for the noun (this is why in American English you hear some people refer to “deers” or “gooses” instead of the correct plural forms“deer” and “geese”). This often starts in childhood because of naivete and becomes a hard-to-break habit. Because of this overwhelming tide of common usage, media has adopted the same term. A few outlets have done the research to find the correct term of “LEGO brand building bricks,” but they are few and far between. The most interesting situations occur when a prerecorded piece which correctly refers to “LEGO brand building bricks” (or similar preferred description) which is then followed by a live commentator saying, “Yeah, I loved Legos as a kid, too.”

Well… that depends. Did you mean LEGO the company, LEGO the brand, or LEGO the product? Unfortunately, LEGO (the company) has kind of mooshed these together.

LEGO (the company) was originally founded as a carpentry shop— Ole Kirk Christiansen took over the “Billund Woodworking and Carpenter’s Shop”, which was founded in 1895 (technically, I expect it had the equivalent name in Danish). When Ole bought it in 1916, it doesn’t seem like he changed the name. It was probably still referred to similarly, without a real formal business name.

In 1932, he had to close down temporarily, and then reopened after getting some loans, and started making toys. But they didn’t have a brand name on them— they were just … the toys they made. So in 1934, Ole decided to give them an official name: “LEGO” (from the Danish “Leg Godt”, for “Play Well”).

It’s not clear to me whether or not he renamed the business to “LEGO” at that point, or if “LEGO” was merely the brand they started using on all their toys. After all, I believe they were still producing other wooden products as well, such as stepladders, ironing boards, etc. But certainly, the name “LEGO” was added to all their toys at the time, so that people would associate the brand name with the quality craftsmanship that they were made with.

Fast forward to 1949. I don’t believe they were still making other products at this point OTHER than toys, although I’m not totally sure. I expect that they also started calling their company “LEGO” by this point, possibly after the fire in 1942 (they had at least 4 separate fires that impacted their business over the years). LEGO now was making plastic toys (started in 1947), and also introduced the building-brick product in 1949. But they didn’t call it “LEGO”. They called the product “Automatic Binding Bricks”.

So, that’s the first name of the LEGO building-brick product. BUT, they also weren’t terribly fond of that lengthy name. Godtfred Kirk Christiansen (the founder’s son, who was gradually getting more prominent in the company) absolutely loved the bricks, and thought they were the future of the business. He was looking to catapult the company to the next level of success around the building bricks, around 1954–1955.

Around that time, LEGO also started switching to the name “Mursten”, meaning “Bricks” in Danish. Hence, the product was now referred to as “LEGO Mursten”— the same way that we might say “Hasbro Transformers”.

But people were complaining about LEGO’s Mursten product. They had some issues with it that made it annoying to work with. So in 1958, they re-designed the way that they were made, using a stud-and-tube system that was patented in many countries. Further, they now started calling this the “LEGO System”.

And now, the confusing part.

In 1960, they had another fire. It destroyed the wooden toys division of the company (which Godtfred’s other family members were running), and Godtfred had to decide if they would rebuild it. He decided not to. By this time, the plastic building bricks were the vast bulk of LEGO’s product line and income. He made the conscious decision to ONLY keep making the building bricks, and leave the other products fade away. (His brothers disagreed, and started a new company, “Bilofix” which continued making wooden toys.)

And so, at this point, LEGO the company / Brand name was really only making ONE product (the building bricks), which no longer really needed any specific product designation. They were just “LEGO”.

This has become a little odd in later years, since LEGO has had several other building products (DUPLO, ZNAP, Scala, Quatro, etc, some of which have very different building methods), and even had made totally different things (like a clothing line in the late 1990s!)

So, the answer is it depends on what you mean!

The company? Then maybe “Billund Woodworking and Carpenter’s Shop”.

The brand name? Then probably nothing— it was always LEGO or nothing!

The product? Then maybe “Automatic Binding Bricks”, “Mursten” or “System”!

To answer my own question - mostly I use Lego’s own naming convention, with a few exceptions:

These are ‘slippers’:

And my brothers and I referred to these as ‘biggies’ when we were kids. No idea why, but it’s stuck well into my 40’s:

So, first off, “LEGO” is kind of unfortunately named. “LEGO” is a company, like Hasbro, Mattel, or Bandai. But essentially their only product is … not really properly named. People call their product “LEGO”, which is strange.

But I think the answer you’re looking for is “Automatic Binding Bricks”. But let’s look at the history anyway:

In 1932, Ole Kirk’s woodworking shop started making toys, but they didn’t have a brand name.

In 1934, they came up with a brand name of “LEGO” for their wooden toys. But they didn’t have any plastic bricks yet.

In 1947, they started making plastic toys, which were also branded as “LEGO”.

In 1949, LEGO started making its now famous building bricks, which were called “Automatic Binding Bricks”. These were a copy of KiddiCraft’s similar product from 1945, which were called “Self-Locking Bricks”.

In the 1950s, LEGO started referring to its building bricks as “Mursten”, which means “brick” in Danish.

In 1958, they got the patent on their new stud-and-tube building system, which sometimes is used to delineate “Automatic Binding Bricks” and “modern LEGO bricks”.

In 1960, after a fire destroyed their wooden toys division (they had a lot of fires at LEGO, actually), they decided to abandon wooden toys completely. They also pretty much stopped making anything else OTHER than their plastic building bricks.

Henceforth, LEGO has become used to refer to both the company and the product, even though that’s … confusing.

If you want to get technical, LEGO has several different building systems for its building products, including:

• LEGO System (the normal stud-and-tube style building pieces)
• LEGO Technic (axles, gears, etc)
• LEGO DUPLO (large-size stud-and-tube pieces)
• LEGO Quatro (even-larger size stud-and-tube building system)
• LEGO Soft (an-even-yet-larger size stud-and-tube system)
• LEGO Modulex (a micro-sized stud-and-tube system)
• LEGO Clikits (a system for decorative items like jewelry and other things)
• LEGO Scala (a dollhouse furniture system, as well as a jewelry lineup from the late 1970s)
• LEGO ZNAP (a system kind of similar to K’Nex)

They’ve also done a few other oddball products that aren’t necessarily named per se, like the constraction figures system and the system for Galidor. And some other stuff that’s arguably its own system like LEGO Toolo or LEGO Muji.

LEGO’s original name was LEGO. It is the shortened Danish form of “leg godt”, which in English means “play well”. Incidentally, lego also means “assemble” in Latin (it also means “read”). So LEGO is a really fortunate name.
The patent from 1958 says “Box-shaped elements with coupling stubs”. The patent on the interlocking bricks expired in 1989.

What is unfortunate, is that lego’s has become a colloquially synonymous name for toy building bricks produced by other firms. Best comparison may be the word “hoover”, which in the UK is synonymous with vacuum-cleaners, not just those made by the The Hoover Company.

LEGO’s 1958 patent.

My mental names for various bricks probably have to do with my dyscalculia. A “one block” should be pretty obvious. What you and your brothers called “biggies” were my “two blocks,” and a 2x2 was a “four block” (likewise, a 2x4 = “eight block”). I tended to name them mentally, and when playing with my sister, after the total number of pips on top. (They didn’t really start having specialized parts, or I didn’t, until the Lego Space series launched. Today, my nephew and niece are incredulous that when the first Lego Castle sets came out, we had to build the horses.)

You might think that a 1x4 would have just as much right to be called a “four block,” and that my nomenclature would be confusing. Well, yeah. I imagine so. I didn’t say that it was a good system, just that it was my system.