The term "rounding" is used quite broadly in math and computer science to mean adjusting a number to a certain multiple. Not only can you round a real number to an integer in various ways, but you can round a real number to a multiple of .1, say.

It is probably true that in formal math, the word "round" tends not to be used, in favor of something like defining floor(x) to be: the largest integer that does not exceed x.