Where does “Luas” come from?

Luas (English) comes from Irish luas, from Old Irish lúas — swiftness, speed.

Ancestry of “Luas”, step by step

Step	Language	Word	Meaning
1	Irish	luas	speed, velocity; earliness
2	Old Irish	lúas	swiftness, speed

Luas — Etymology, Origin & Word History | Etymology Explorer