For research purposes, the limits of  “genealogical time” —when it is possible to identify individuals by the use of surnames and titles in records— reach back about 900 years in Europe. The earliest surname designations were probably instituted by Chinese bureaucracies one or two millennia BCE; in Europe, however, surnames first came into use in the 12th century and did not become universal for several hundred years. The practice is generally believed to have arrived in Britain with William the Conqueror in 1066 AD.

Modern surname spellings, which evolved and changed with migration, invasion, and cultural pressures, are unreliable indicators of ethnic origins. One early Connecticut family, for example, employed Gozzard, Gozard, Gossard, Gosard, and Gossart interchangeably throughout the 18th century, but by the 19th century had standardized on the more familiar Goddard and Godard.

The very earliest sources of the Goddard surname may be Northern Germanic tribes, notably those we know as Angles, Saxons, Norse, and Normans. Most common variants of the surname Goddard probably evolved from one of two different European forms: one containing consonants in the middle, and one containing sibilants.

This surname, found recorded variously in England and France, is of Norman origin, and is from the personal name "Golhard" composed of the Germanic elements "god” (good) or "god, got” (god), and "hard” (hardy, brave, strong). The name was introduced into Britain by the Normans after the Invasion of 1066, and it was popular in Europe during the Middle Ages as a result of the fame of St. Goddard (or Gotthard), an 11th Century bishop of Hildesheim, who founded a hospice on the pass from Switzerland to Italy that bears his name. The name is recorded as a surname in variant forms throughout Europe: Godard, Goddard and Godart in England; Goudard and Godar in France; Gotthard, Godehard and Goddert in Germany; and Goedhard and Goedhart in Holland.

This unusual surname is a variant of Gossart, which is of Anglo-Saxon and French origin, and has two possible sources. The first source is from an occupational name for a keeper of geese, derived from the Middle English (1200 - 1500) "goseherde,” from the Old English pre 7th Century "gos” (goose), and the Old English "hierde” (herdsman, keeper, from "heord,” herd, flock). The second source is a pejorative of Gosse, which is derived from the Old French given name "Gosse,” representing the Germanic personal name "Gozzo,” a short form of various compound names with the first element "god” (good) or "god, got” (god). 

The Goddard Association of Europe offers a learned examination of the Origins of the Surname as it pertains to the British Isles in particular.