macronucleus

mac·ro·nu·cle·us

noun \ˌmak-rō-ˈn(y)ü-klē-əs\

plural mac·ro·nu·clei \-ˌī\ also mac·ro·nu·cle·us·es

Definition of MACRONUCLEUS

: a relatively large densely staining nucleus of most ciliate protozoans that is derived from micronuclei and controls various nonreproductive functions—compare micronucleus

—mac·ro·nu·cle·ar \ˌmak-rō-ˈn(y)ü-klē-ər\ adjective