germinalPronunciation: /ˈdʒəːmɪn(ə)l/Definition of germinal adjective [attributive] relating to or of the nature of a germ cell or embryo. in the earliest stage of development:a germinal idea providing material for future development:de Beauvoir’s germinal book The Second SexDerivatives germinally adverb Origin: early 19th century: from Latin germen, germin- 'sprout, seed' + -algerminal in other Oxford dictionaries Definition of germinal in the US English dictionary