nucleomorph
/ˈnjuːklɪə(ʊ)moːf/Cell Biol.
noun
An organelle found in the chloroplasts of cryptomonads and certain other protists which is bounded by a double membrane, contains genetic material, and is thought to represent the vestigial nucleus of an endosymbiotic algal cell.
Origin
1970s. From nucleo- + -morph.