macronucleus
noun
mac·ro·nu·cle·us ˌma-krō-ˈnü-klē-əs 
-ˈnyü-
: a relatively large densely staining nucleus of most ciliate protozoans that is derived from micronuclei and controls various nonreproductive functions
macronuclear
ˌmak-rō-ˈnü-klē-ər
adjective -ˈnyü-
nonstandard -kyə-lər
Word History
Etymology
macro- + nucleus
First Known Use
1887, in the meaning defined above
Medical Definition
macronucleus
noun
mac·ro·nu·cle·us ˌmak-rō-ˈn(y)ü-klē-əs
plural macronuclei -ˌī also macronucleuses
also macronucleuses : a relatively large densely staining nucleus of most ciliate protozoans that is derived from micronuclei and controls various nonreproductive functions compare micronucleus