hit the hay

VERB
11 LETTERS · STARTS WITH H

hit the hay is a valid 11-letter word worth 21 points in Scrabble and 17 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
H4I1T1T1H4E1H4A1Y4
4 + 1 + 1 + 0 + 1 + 4 + 1 + 0 + 4 + 1 + 4 =21 PTS
DOUBLE WORD → 42TRIPLE WORD → 63
MEANING

What does hit the hay mean?