lantern jaw

NOUN /læntərn_dʒɔ/
11 LETTERS · 2 SYLLABLES · STARTS WITH L

lantern jaw is a valid 11-letter word worth 20 points in Scrabble and 25 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
L1A1N1T1E1R1N1J8A1W4
1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 8 + 1 + 4 =20 PTS
DOUBLE WORD → 40TRIPLE WORD → 60
MEANING

What does lantern jaw mean?