The word "cleavage" means splitting or separating.
The egg fuses with the sperm, each containing 23 chromosomes, resulting in a diploid somatic cell. This phenomenon, termed as fertilization, occurs in the ampulla followed by cleavage. The cytoplasm of the zygote continues to divide to form smaller blastomeres. A group of blastomeres formed as a result of cleavage is termed as pre-embryo.
Cleavage is defined as the process by which the fertilized egg proliferates repeatedly to produce a large number of daughter cells.