acrosome
noun
ac·ro·some ˈa-krə-ˌsōm 
: an anterior prolongation of a spermatozoon that releases egg-penetrating enzymes
acrosomal
ˌa-krə-ˈsō-məl
adjective 
Example Sentences
Recent Examples on the Web Next, the acrosome, a vesicle inside the sperm cell’s head, fuses with the outer layer of the egg, igniting the release of enzymes that ease the route inside. 
Randi Hutter Epstein, New York Times, 17 Apr. 2020 This study will also be the closest off-planet look at the acrosome, which develops inside the head and acts like an organ. Joe Pappalardo, Popular Mechanics, 16 July 2018
Randi Hutter Epstein, New York Times, 17 Apr. 2020 This study will also be the closest off-planet look at the acrosome, which develops inside the head and acts like an organ. Joe Pappalardo, Popular Mechanics, 16 July 2018 Word History
Etymology
borrowed from German Akrosoma, from akro- acro- + -soma -some entry 3
First Known Use
1899, in the meaning defined above
Medical Definition
acrosome
noun
ac·ro·some ˈak-rə-ˌsōm
: an anterior prolongation of a spermatozoon that releases egg-penetrating enzymes