closed sentence

15 LETTERS · STARTS WITH C

closed sentence is a valid 15-letter word worth 19 points in Scrabble and 24 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

C3L1O1S1E1D2S1E1N1T1E1N1C3E1

3 + 1 + 1 + 1 + 1 + 2 + 0 + 1 + 1 + 1 + 1 + 1 + 1 + 3 + 1 =19 PTS

DOUBLE WORD → 38TRIPLE WORD → 57

MEANING

What does closed sentence mean?