- bì
- bi, bìbe Irish bí, be thou, Old Irish bíu, sum, bí be thou, Old Welsh bit, sit, bwyf, sim, Middle Breton bezaff. Proto-Celtic bhv-ijô, for Old Irish bíu, I am; Latin fio; English be; Indo-European root bheu, be. See bha. Stokes differs from other authorities in referring bíu, bí to Celtic beiô, root bei, bi, live, as in bith, beatha, Latin vivo, etc.
Etymological dictionary of the Gaelic language. Alexander Gairm Publications. 1982.