Yes, zip is a Scrabble word!
...and is worth 14 points in Scrabble, and 15 points in Words with Friends
zip
Verb
1. Close with a zipper
2. Move very fast
Noun
1. A quantity of no importance
2. A code of letters and digits added to a postal address to aid in the sorting of mail
3. Forceful exertion
4. A fastener for locking together two toothed edges by means of a sliding tab
What Scrabble words can I make with the letters in zip?
2 Letter Words