Definition of macronucleus in English:

macronucleus

noun

Zoology
  • The larger of the two types of nuclei of ciliate protozoans, responsible for the control of most cellular processes other than sexual reproduction.

Origin

Late 19th century; earliest use found in Journal of the Royal Microscopical Society. From macro- + nucleus.

Pronunciation

macronucleus

/ˌmakrəʊˈnjuːklɪəs/