cytoplasmPronunciation: /ˈsʌɪtə(ʊ)plaz(ə)m/Definition of cytoplasm noun [mass noun] Biology the material or protoplasm within a living cell, excluding the nucleus. Derivatives cytoplasmicPronunciation: /-ˈplazmɪk/ adjective cytoplasm in other Oxford dictionaries Definition of cytoplasm in the US English dictionary