sound barrier

NOUN /saʊnd_'bæriər/
13 LETTERS · 3 SYLLABLES · STARTS WITH S

sound barrier is a valid 13-letter word worth 15 points in Scrabble and 18 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
S1O1U1N1D2B3A1R1R1I1E1R1
1 + 1 + 1 + 1 + 2 + 0 + 3 + 1 + 1 + 1 + 1 + 1 + 1 =15 PTS
DOUBLE WORD → 30TRIPLE WORD → 45
MEANING

What does sound barrier mean?

NOUN · 1 SENSE
1

The increase in aerodynamic drag as an airplane approaches the speed of sound.