What It Scores
ATOP is a valid word in the tournament list this site uses. Tile values only, before any premium square: 6 in Scrabble and 7 in Words With Friends. The letters break down as A1 T1 O1 P3.
Words Made From The Letters In ATOP
16 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 (10)
2 letter words (6)
Longer Words Containing ATOP
ATOP 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.