Webster's Revised Unabridged Dictionary · 1913

Heterogamy

Heterogamy , noun

[See Heterogamous.]

1.
(Botany) The process of fertilization in plants by an indirect or circuitous method; -- opposed to orthogamy.
2.
(Biology) That form of alternate generation in which two kinds of sexual generation, or a sexual and a parthenogenetic generation, alternate; -- in distinction from metagenesis, where sexual and asexual generations alternate. — Claus & Sedgwick