congruent adj.

word-forming element meaning "together, with," sometimes merely intensive; it is the form of com- used in Latin before consonants except -b-, -p-, -l-, -m-, or -r-. In native English formations (such as costar), co- tends to be used where Latin would use con-.

mid-15c., "suitableness or appropriateness of one thing to another," from Latin congruentia "agreement, harmony, congruity," from congruen-, present-participle stem of congruere "agree, correspond with," literally "to come together," from assimilated form of com "with, together" (see con-) + a lost verb *gruere, *ruere "fall, rush" (see congruent). Meaning "fact or condition of according or agreeing" is from 1530s. Related: Congruency.