shell construction

18 LETTERS · STARTS WITH S

shell construction is a valid 18-letter word worth 24 points in Scrabble and 30 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

S1H4E1L1L1C3O1N1S1T1R1U1C3T1I1O1N1

1 + 4 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 1 + 1 =24 PTS

DOUBLE WORD → 48TRIPLE WORD → 72

MEANING

What does shell construction mean?