ladies' slipper

NOUN
15 LETTERS · STARTS WITH L

ladies' slipper is a valid 15-letter word worth 18 points in Scrabble and 22 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
L1A1D2I1E1S1'0S1L1I1P3P3E1R1
1 + 1 + 2 + 1 + 1 + 1 + 0 + 0 + 1 + 1 + 1 + 3 + 3 + 1 + 1 =18 PTS
DOUBLE WORD → 36TRIPLE WORD → 54
MEANING

What does ladies' slipper mean?