The term sperm is derived from the Greek word (σπέρμος) spermos (meaning "seed") and refers to the male reproductive cells. Sperm cells are the smaller gametes involved in fertilization in anisogamy and oogamy. In these types of sexual reproduction, there's a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. A uniflagellar sperm cell that's motile is also referred to as spermatozoon, whereas… (More on Sperm)