Is SISS a valid Scrabble word?
YES — SISS is a valid Scrabble word 4 points
Scrabble® and Words With Friends® points for SISS
SISS is a valid Scrabble US/CAN word worth 4 points:
S1I1S1S1
SISS is valid in Scrabble UK (World) —
S1I1S1S1
SISS is not valid in Words With Friends.