n. [ Spermatozoon + Gr. e'i^dos form. ] (Biol.) The male germ cell in animals and plants, the essential element in fertilization; a microscopic animalcule-like particle, usually provided with one or more cilia by which it is capable of active motion. In animals, the familiar type is that of a small, more or less ovoid head, with a delicate threadlike cilium, or tail. Called also spermatozoon. In plants the more usual term is antherozoid. [ 1913 Webster ]