congruentyoudaoicibaDictYouDict[congruent 词源字典]
congruent: [15] Etymologically, triangles that are congruent ‘come together’ or ‘agree’ – that is, are similar. The word comes from congruēns, the present participle of Latin congruere ‘come together, meet, agree’. This was a compound verb formed from the prefix com- ‘together’ and a verb, *gruere, not found elsewhere (some have linked it with Latin ruere ‘fall’ – ultimate source of English ruin – in which case congruere would have meant literally ‘fall together’, but others have seen a connection with Greek zakhrēēs ‘attacking violently’). Incongruous is a 17thcentury adoption from Latin incongruus.
[congruent etymology, congruent origin, 英语词源]
congruent (adj.)youdaoicibaDictYouDict
early 15c., "suitable, proper," from Latin congruentem (nominative congruens) "agreeing, fit, suitable," present participle of congruere, literally "to come together, agree, correspond with," from com- "with" (see com-) + a lost verb *gruere, *ruere "fall, rush," perhaps from PIE *ghrei- "to rub, grind" (see chrism). Geometry sense attested by 1706.