Where does “esna” come from?

esna (Romansch) comes from Latin asina, from Latin asinus, from Latin acinus, from Latin acies, from Proto-Indo-European h₂eḱ- — sharp.

esna (Romansch): female donkey, ass

Definitions

Step	Language	Word	Meaning
1	Latin	asina	nominative feminine singular of asinus;...
2	Latin	asinus	a donkey, an ass; an ass, an idiot, a dolt, a...
3	Latin	acinus	a berry, especially the grape; the seed of a...
4	Latin	acies	sharp edge or point; battle line; battle,...
5	Proto-Indo-European	h₂eḱ-	sharp