nebenkern
/ˈneɪb(ə)nkəːn/ /ˈneɪb(ə)nkɛːn/Cell Biol.
noun
Any of various cytoplasmic structures situated beside, associated with, or resembling a cell nucleus; specifically the helical mitochondrial sheath surrounding the flagellum in the midpiece of a spermatozoon.
Origin
Late 19th century; earliest use found in Science. From German Nebenkern from neben beside + Kern kernel, nucleus.