Pronunciation: (mak"rō-nOO'klē-us, -nyOO'-), [key]
the larger of the two types of nuclei occurring in ciliate protozoans, having a multiple set of chromosomes and functioning in cell metabolism and protein synthesis. Cf. micronucleus.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.