rest period

NOUN
11 LETTERS · STARTS WITH R

rest period is a valid 11-letter word worth 13 points in Scrabble and 14 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
R1E1S1T1P3E1R1I1O1D2
1 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 2 =13 PTS
DOUBLE WORD → 26TRIPLE WORD → 39
MEANING

What does rest period mean?