Where does “crosbhacart” come from?

crosbhacart (Irish) comes from Irish cros-, from Irish cros, from Old Irish cros, from Latin crux, from Proto-Italic *kruks, from Proto-Indo-European sḱer- — to caw, crow.

crosbhacart (Irish): T-square

Definitions

T-square

Ancestry of “crosbhacart”, step by step

Step	Language	Word	Meaning
1	Irish	cros-	cross-
2	Irish	cros	cross; crosspiece; trial, affliction
3	Old Irish	cros	cross
4	Latin	crux	wooden frame on which criminals were crucified,...
5	Proto-Italic	*kruks	—
6	Proto-Indo-European	sḱer-	to caw, crow

Every word from Proto-Indo-European sḱer- →Every word from Proto-Italic *kruks →Every word from Latin crux →