oog·a·mous \(ˈ)ō|ägəməs\adjective Etymology:o- + -gamous 1.of sexual reproduction: characterized by fusion of a small actively motile male gamete and a large immobile female gamete — compare anisogamous, heterogamous, isogamous 2.: having oogamous reproduction • oog·a·my\ōˈägəmē\noun-es