Yes, four is a Scrabble word!
...and is worth 7 points in Scrabble, and 8 points in Words with Friends
four
Adjective
1. Being one more than three
Noun
1. The cardinal number that is the sum of three and one
2. A playing card or domino or die whose upward face shows four pips
What Scrabble words can I make with the letters in four?
3 Letter Words
2 Letter Words