mid-15c., "to make shorter," from Latin abbreviatus, past participle of abbreviare "to shorten, make brief," from ad "to" (see ad-) + breviare "shorten," from brevis "short, low, little, shallow" (from PIE root *mregh-u- "short").
Specifically of words by 1580s. Also sometimes 15c. abbrevy, from French abrevier (14c.), from Latin abbreviare. Related: Abbreviated; abbreviating.
Biblical title of honor, literally "father," used as an invocation of God, from Latin abba, from Greek abba, from Aramaic (Semitic) abba "the father, my father," emphatic state of abh "father." Also a title in the Syriac and Coptic churches.
It is used in the New Testament three times (Mark xiv. 36, Rom. viii. 15, Gal. iv. 6), in each instance accompanied by its translation, "Abba, Father," as an invocation of the Deity, expressing close filial relation. Either through its liturgical use in the Judeo-Christian church or through its employment by the Syriac monks, it has passed into general ecclesiastical language in the modified form of abbat or abbot .... [Century Dictionary]
early 15c., abbreviacioun, "shortness; act of shortening; a shortened thing," from Old French abréviation (15c.) and directly 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" (from PIE root *mregh-u- "short").
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).