Yes, dada is a Scrabble word!
...and is worth 6 points in Scrabble, and 6 points in Words with Friends
dada
Noun
1. An informal term for a father; probably derived from baby talk
2. A nihilistic art movement (especially in painting) that flourished in Europe early in the 20th century; based on irrationality and negation of the accepted laws of beauty
What Scrabble words can I make with the letters in dada?
3 Letter Words
2 Letter Words