Why is meiosis referred to as a process of cell reduction

Because in meiosis the number of chromosomes becomes half.

Explanation:

Meiosis is called reductional division because in meiosis the number of chromosomes gets half in daughter cells after cell division.

Meiosis takes place in gametic cells. In meiosis four haploid cells are produced from one diploid mother cells. Two cell division takes place in meiosis. During the first cell division, the chromosome number gets half due to the separation of a homologous chromosome which makes the daughter cell haploid.

Therefore as chromosome number in daughter cell becomes half so meiosis is referred to as a process of cell reduction.