Where does “daltach” come from?

daltach (Irish) comes from Irish ách, from Old Irish acht, from Proto-Celtic extos, from Proto-Indo-European eǵʰs — out; from, out of.

daltach (Irish): of or belonging to foster children; having foster...

Definitions

daltach traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Irish	ách	Alternative form of ach
2	Old Irish	acht	but; provided; inflection of aigid: ##...
3	Proto-Celtic	extos	except, but
4	Proto-Indo-European	eǵʰs	out; from, out of

Step	Language	Word	Meaning
1	Irish	dalta	foster child; pupil; disciple; student;...
2	Old Irish	daltae	foster-son, fosterling, nursling, ward; pupil,...