On Sat, 27 May 2000 13:46:42 -0400 (EDT), John Conway wrote: >On Wed, 24 May 2000, Walter Whiteley wrote: > >> I don't have my book on the origns of math words, >> but I believe the root meaning is 'throw together'. > > The verb "congruere" existed already in classical >Latin with the meaning of "to come together, or agree", >and the word "congruent" is still occasionally used in >ordinary English with this meaning, which is congruent >(!) with its geometrical one. > > However, it seems that nobody really understands >the etymology of this word (after "con" which is the >"together" part). It's obviously based on a lost >Latin verb "gruere", but nobody knows what that could >have meant, since the only other compound in which it >appears is "ingruere", which meant "to rush or break >into". > > John Conway
Actually, "gruere" comes from the latin word grui which means to be in harmony with.
So congruent translates to mean together in harmony with