vitellogeninPronunciation: /vɪˌtɛlə(ʊ)ˈdʒɛnɪn, ˌvɪt(ə)ləʊˈdʒɛnɪn/Definition of vitellogenin noun Biochemistry a protein present in the blood, from which the substance of egg yolk is derived. Origin: 1960s: from vitellus + -gen + -in1vitellogenin in other Oxford dictionaries Definition of vitellogenin in the US English dictionary