extension rule

14 LETTERS · STARTS WITH E

extension rule is a valid 14-letter word worth 20 points in Scrabble and 24 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
E1X8T1E1N1S1I1O1N1R1U1L1E1
1 + 8 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 1 + 1 + 1 + 1 =20 PTS
DOUBLE WORD → 40TRIPLE WORD → 60
MEANING

What does extension rule mean?

1