Of Celtic (Arthurian) origin, a Cornish form of the name of King Arthur's unfaithful Guinevere. At the beginning of the 20th century, the name was merely a Cornish curiosity, but since then it has become enormously popular all over the English-speaking world, partly due to the influence of the film star Jennifer Jones (b. 1919 as Phyllis Isley). Another factor in its rise was probably Bernard Shaw's use of it for the character of Jennifer Dubedat in The Doctor's Dilemma (1905). See also Gaynor. More recent well-known bearers include the American tennis player Jennifer Capriati (b. 1976) and the British comedienne Jennifer Saunders (b. 1958).
English and Dutch: from the Germanic byname mentioned at Ernst. However, Reaney cites medieval evidence for Norman spellings such as Ernais, and derives it from a Germanic personal name Arn(e)gis, possibly composed of the elements arn ‘eagle’ + gīsil ‘pledge’, ‘hostage’, ‘noble youth’ (see Giesel). The name may have been altered by folk etymology to coincide with the word meaning ‘combat’. Compare Harness.