1) Amphimixis 2) Sexual reproduction 3) The union of anisogametes 
Anisogamy (noun) (also called heterogamy) refers to a form of sexual reproduction involving the union or fusion of two dissimilar gametes (differing either in size alone or in size and form) — anisogamous, anisogamic, (adj.). The smaller gamete is considered to be male (sperm cell), whereas the larger gamete is regarded as female (egg cell). The...
Sexual reproduction where one sex produces sex cells much larger (egg) than thoseof the other (sperm). As seen in cats and humans. 
<biology> A condition where the gametes of a species have different sizes. In general, the smaller, more mobile gamete is male and the larger one which is packed with food and other things to give the potential zygote a good start (and is less mobile as a result) is the female. The principle behind anisogamy is a division of the labour necess...
Mode of sexual reproduction in which the two gametes are of different sizes.
Type: Term Pronunciation: an′-i-sog′ă-mē Definitions: 1. Fusion of two gametes unequal in size or form; fertilization as distinguished from isogamy or conjugation.
[n] - (biology) reproduction by the union or fusion of two differing gametes (especially differing in size)
anisogamy 1. Marriage between persons of unequal age, especially when there is a considerable age difference. 2. In botany, the union of two unequal gametes in reproduction.3. Fusion of two gametes unequal in size or form; fertilization as distinguished from isogamy or conjugation.
noun (biology) reproduction by the union or fusion of two differing gametes (especially differing in size)
the union of anisogametes.