What It Scores
PACK is a valid word in the tournament list this site uses. Tile values only, before any premium square: 12 in Scrabble and 14 in Words With Friends. The letters break down as P3 A1 C3 K5.
Words Made From The Letters In PACK
4 shorter words come out of these tiles. On a board that matters more than the long play, because a short word on a premium square often beats a long one on plain squares.
3 letter words (2)
2 letter words (2)
Longer Words Containing PACK
PACK appears inside each of these, which is what makes it worth knowing as a hook.
Next: the Word Unscrambler for any letters at all. Full entry and definition at Merriam-Webster.