''Geas''

A geas is a spell that places a compulsion or vow on the object of the spell. In the Lord Darcy Series, it occurs in the story A Case of Identity.

The word originates in Old Irish, and also occurs with the same meaning in Scottish Gaelic. Further it occurs in the language Northern Sámi, the language of the Lapp people from northern Finalnd and along the north coast of Norway in our timeline. .

In the Lord Darcy timeline, this would suggest a westward movement of the word and concept from northern Scandinavia through Scotland and thus to Ireland, brought by the Tuatha de Danann circa 1200 BC, along with the Talent. The use of an Irish word to descrive it suggests there is no similar concept in the originating languages of Anglo-French, or in Church Latin, though the concept probably exists. In our timeline the word is absent from the Goidelic Celtic languages (ie, Breton, Cornish and Welsh) which further suggests an origin with the 'Dedannans' which bypassed the more southern Celtic languages.