1. To cut short, to reduce, or to compress a word or phrase into a shorter form that is intended to represent the full form: People can abbreviate the word "Mister" into "Mr."
2. To curtail, to trim, or to shorten: Since time was short, Maurice abbreviated his visit with his friends.
3. Etymology: the brev- in abbreviate comes from the Latin brevis, "short", which is also the source of brief; so, naturally, abbreviate means "to make briefer, to make shorter" by combining or omitting something; for example, changing "dozen" to "doz." and "quart" to "qt.".