abbreviation (n.) Look up abbreviation at
mid-15c., "act of shortening; a shortened thing," from Middle French abréviation (15c.), from Late Latin abbreviationem (nominative abbreviatio), noun of action from past participle stem of abbreviare "shorten, make brief," from Latin ad "to" (see ad-) + breviare "shorten," from brevis "short, low, little, shallow" (see brief (adj.)).

From 1580s specifically of words. Technically a part of a word, usually the initial letter or syllable, used for the whole word but with no indication of the rest of the word (as abbr. for abbreviation or abbreviate). A contraction is made by elision of certain letters or syllables from the body of a word but still indicates its full form (as fwd. for forward; rec'd. for received).