The remainder of a group are the things or people that still remain after the other things or people have gone or have been dealt with.

In arithmetic, the remainder is the amount that remains when one amount cannot be exactly divided by another. For example, if you divide 22 by 7, the answer is 3 and the remainder is 1.

If a book is remaindered, it is sold at a reduced price because it has not been selling very well and will not be published again.

A remainder is a book that has been remaindered.