Where does “Lachtnán” come from?

Lachtnán (Old Irish) comes from Old Irish Lachtnae, from Old Irish lachtna, from Old Irish lacht, from Latin lác, from Proto-Indo-European ǵlákts — milk.

Ancestry of “Lachtnán”, step by step

Step	Language	Word	Meaning
1	Old Irish	Lachtnae	—
2	Old Irish	lachtna	milk coloured; gray, dun; the colour of...
3	Old Irish	lacht	milk
4	Latin	lác	milk
5	Proto-Indo-European	ǵlákts	milk

Every word from Proto-Indo-European ǵlákts →Every word from Latin lác →Every word from Old Irish lacht →