From Middle Radestrian bivra, from Old Radestrian biwræ, from Proto-Radic *biwer, *biwišjir, from Proto-Hirdic *bikhwés, from Proto-Laenkean *ᵐbi-k(ʰ)wé-.
From Middle Radestrian bvar, from Old Radestrian bwær, from Proto-Radic *bwær, from Proto-Hirdic *buǽs, from Proto-Laenkean *ᵐbuǽs, from the Proto-Laenkean root *ᵐbæw-.