shell expansion

15 LETTERS · STARTS WITH S

shell expansion is a valid 15-letter word worth 26 points in Scrabble and 30 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1H4E1L1L1E1X8P3A1N1S1I1O1N1

1 + 4 + 1 + 1 + 1 + 0 + 1 + 8 + 3 + 1 + 1 + 1 + 1 + 1 + 1 =26 PTS

DOUBLE WORD → 52TRIPLE WORD → 78

MEANING

What does shell expansion mean?