british monetary unit

NOUN
21 LETTERS · STARTS WITH B

british monetary unit is a valid 21-letter word worth 29 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
B3R1I1T1I1S1H4M3O1N1E1T1A1R1Y4U1N1I1T1
3 + 1 + 1 + 1 + 1 + 1 + 4 + 0 + 3 + 1 + 1 + 1 + 1 + 1 + 1 + 4 + 0 + 1 + 1 + 1 + 1 =29 PTS
DOUBLE WORD → 58TRIPLE WORD → 87
MEANING

What does british monetary unit mean?