1. That process in the division of germ cells by which the number of chromosomes is reduced from the double or diploid number typical of somatic cells to the halved or haploid number characteristic of gametes.
2. The nuclear changes which take place in the last two cell divisions in the formation of germ cells.

The chromosomes separate from one another once, but the cell body divides twice with the result that the nucleus of the mature egg, or sperm, contains the reduced (haploid) number of chromosomes.

3. In rhetoric, an understatement, often giving the effect of irony or humor, by representing a fact, thing, deed, etc., as being smaller than it really is.