A northern English and Scottish surname originating as a patronymic.

Thecla letha, a species of theclan hairstreak moth.

A branching stochastic process arising from the statistical investigation of the extinction of family names, which are modelled as patrilineal, while offspring are randomly either male or female, and names become extinct if holders die without male descendants. It is useful in understanding human Y-chromosome DNA haplogroups.

plural of Galton-Watson process