Modulo

"21 and 84 are congruent to each other modulo 9, since both numbers leave the same remainder, 3, when divided by 9.; Thus 21 modulo 9 is 3, because when 21 is divided by 9, the remainder is 3.; 21 is congruent to 3 modulo 9."

""A is the same as B modulo C" means A is the same as B except for differences accounted for by C."

"In the Lisp programming language, the "tail recursion modulo cons" technique allows functions that would be tail recursive but for a cons call to be transformed into a tail recursive form.; All mammals, modulo the monotremes, give birth to live young."