Where does “fainleóc” come from?

fainleóc (Middle Irish) comes from Old Irish ainnel, from Proto-Celtic wesnālā, from Proto-Celtic wesr-, from Proto-Indo-European wósr̥ — spring.

Ancestry of “fainleóc”, step by step

StepLanguageWordMeaning
1Old Irishainnel—
2Proto-Celticwesnālāswallow
3Proto-Celticwesr-spring
4Proto-Indo-Europeanwósr̥spring
Every word from Proto-Indo-European wósr̥ →Every word from Proto-Celtic wesr- →Every word from Proto-Celtic wesnālā →