Is “Alt” a Scrabble word?
Yes
ALT
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Alt
noun
1.High pitch, of a voice or instrument; especially, the octave above the top line of the treble stave.
2.A state of excitement, a heightened emotional condition.