ad kalendas Graecas
[ahd kah-len-dahs grahy-kahs; English ad kuh-len-duh s gree-kuh s]
at no time; never: from the fact that the Greeks did not reckon dates by calends.
Origin of ad kalendas Graecas
literally, at the Greek calends
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019