amphimixis
noun
am·phi·mix·is ˌam(p)-fi-ˈmik-səs 
plural amphimixes ˌam(p)-fi-ˈmik-ˌsēz
: the union of gametes in sexual reproduction
Word History
Etymology
borrowed from German Amphimixis, from Greek amphi- amphi- + míxis "mixing, mingling," from mig-, base of meígnymi, mígnymi, mignýnai "to mix" + -sis -sis — more at mix entry 1
Note: The term was introduced by August weismann in Amphimixis, oder die Vermischung der Individuen (Jena, 1891), p. 112.
First Known Use
1890, in the meaning defined above
Medical Definition
amphimixis
noun
am·phi·mix·is -ˈmik-səs
plural amphimixes -ˌsēz
1
: the union of gametes in sexual reproduction
2
: the combining of pregenital, anal, and urethral eroticism in the development of genital sexuality