Since you have used the specific word ‘Moksha’, let me answer in the Indian context.

What does Moksha mean?

• In the Sankhya context, a school to which Patanjali belongs, Moksha means the soul disassociating itself from the tangles of the body. Or getting into a state of Kevala. Patanjali calls it as Kaivalya. In that state, the soul knows what it is and remains ever free and blissful.
• In the Vedanta context, Moksha means realizing who you actually are. In the pure Advaitic sense, this involves realizing that you are none other than the one and only Brahma or Atma. It is the mind that was a barrier that shrouded this knowledge. And moksha is removing that shroud.
• In the Buddhist context, Moksha means breaking the endless cycle of births and deaths. There is nobody who attains Moksha, but it is just that the cycle of births and deaths stops. And it is this cycle that infuses the mind with dukha or misery. Breaking of this cycle means end to misery once for all.

How does meditation helps in achieving this Moksha?

• As per Patanjali, prolonged meditation gradually nullifies the mental conditionings, which he calls as Samskaras, and removes all reasons which can cause rebirth. These Samskaras are the seeds that give rise to rebirth. Gradual erasure of them helps one to attain the freedom from rebirth. The Prakriti or the material body, which was all along deluding the soul, stops its play. She (Prakriti) is like a “dancer who stops dancing after exhibiting herself to the disinterested Purusha (soul). Since the soul is freed from rebirth, it naturally attains its free or Kaivalya state, or Moksha.
• A Vedanti considers entanglement with the false identity with the body as the root cause of problems. It is the mind that shrouds the soul from the knowledge of its true nature. When this mind is restrained through meditation, there is nothing that separates embodied soul from the all pervading soul. It is like “breaking the pot which separates the space within the pot from the all pervading the space” – to give the well known Advaitic analogy. If this realization remains even beyond meditation, then it is moksha.
• For a Buddhist, it is the causal chain that drives the sequence of births and deaths. Desire is the driving force behind this chain. When the meditator understands this root cause, and does everything to break this chain of causation, there is no reason for the sequence of births and deaths to continue. No more Karma recorded in the Chitta. So, “like a lamp that has exhausted all the oil, it ceases to burn and attains nirvana or Moksha” – I am quoting Buddha’s words.

These are technical explanations. For a common man, meditation takes you to a higher level of being, where there is lesser suffering. Call it Moksha or whatever ;-)