macronucleus

noun Biology.

1. 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.

noun plural -clei (-klɪˌaɪ)

1. the larger of the two nuclei in ciliated protozoansCompare micronucleus

n.

1. The larger of two nuclei present in ciliate protozoans, which controls the nonreproductive functions of the cell.