restricted propellant

21 LETTERS · STARTS WITH R

restricted propellant is a valid 21-letter word worth 27 points in Scrabble and 33 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

R1E1S1T1R1I1C3T1E1D2P3R1O1P3E1L1L1A1N1T1

1 + 1 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 2 + 0 + 3 + 1 + 1 + 3 + 1 + 1 + 1 + 1 + 1 + 1 =27 PTS

DOUBLE WORD → 54TRIPLE WORD → 81

MEANING

What does restricted propellant mean?