interdepend

VERB /,ɪntərdɪ'pɛnd/
11 LETTERS · STARTS WITH I

interdepend is a valid 11-letter word worth 15 points in Scrabble and 18 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
I1N1T1E1R1D2E1P3E1N1D2
1 + 1 + 1 + 1 + 1 + 2 + 1 + 3 + 1 + 1 + 2 =15 PTS
DOUBLE WORD → 30TRIPLE WORD → 45
MEANING

What does interdepend mean?