a cap-like structure on the tip of a spermatozoon that releases enzymes on encountering the ovum allowing fusion with the ovum in the sexual reproductive process; this part of the process is known as the acrosome reaction
Word origin
C19: from acro- + -some3
acrosome in American English
(ˈækrəˌsoʊm)
noun
a thin sac usually at the head of a sperm cell containing enzymes which dissolve the protective layers of an egg cell