Focus on the pronunciation of nucleus
English definition of “nucleus”
/ˈnu·kli·əs/ n [C] (plural nuclei /ˈnu·kliˌɑɪ/)
› the central part of something › People or things that form the nucleus of something are the most important part of it: These two people will form the nucleus of a new management team to promote sales in South America. › physics A nucleus is the central part of an atom. › biology A nucleus is the central part of a cell that controls its growth.