taghairm

The story

1. Proto-Indo-European · derived from*ǵh₂r̥-smn̥
2. Proto-Celtic · derived from*to-garrman
3. Old Irish · derived fromtogairm
4. Scottish Gaelic · borrowed fromtaghairm
5. English todaytaghairm

Borrowed from Scottish Gaelic taghairm, from Old Irish togairm, from Proto-Celtic *to-garrman, from Proto-Indo-European *ǵh₂r̥-smn̥, from *ǵeh₂r- (“to call, to shout”); compare Irish toghairm (“an invocation, a summons”), from gairm, gair (“to call; to invoke”), ultimately from the same Proto-Indo-European roots. The Encyclopædia Britannica (3rd ed., 1797) suggests a derivation from Scottish Gaelic ta (“a ghost, a spirit”) + gairm (“to call, to cry”), while the editor of an 1871 edition of Sir Walter Scott’s The Lady of the Lake suggested tarbh (“a bull”) or targair (“to foretell”). These etymologies are no longer to be taken seriously.