Yes, CEILIDHS is a Scrabble word!

Letter values in Scrabble US: C 3, E 1, I 1, L 1, I 1, D 2, H 4, S 1.

Is it a valid word?

CEILIDHS is a valid word in the official Scrabble dictionary (US) and the UK Scrabble Dictionary, but not in Words with Friends (ENABLE).

an informal social gathering at which there is Scottish or Irish folk music and singing and folk dancing and story telling