hit the hay/sack, to

hit the hay

To get into bed and go to sleep. I have to get up early for work tomorrow, so I think I'd better hit the hay.
See also: hay, hit

hit the sack

To get into bed and go to sleep. I have to get up early for work tomorrow, so I think I'd better hit the sack.
See also: hit, sack
Farlex Dictionary of Idioms.

hit the hay

 and hit the sack
Fig. to go to bed. I have to go home and hit the hay pretty soon. Let's hit the sack. We have to get an early start in the morning.
See also: hay, hit
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

hit the hay

Also, hit the sack. Go to bed, as in I usually hit the hay after the eleven o'clock news, or I'm tired, let's hit the sack. The first colloquial expression dates from the early 1900s, the variant from about 1940.
See also: hay, hit
The American Heritage® Dictionary of Idioms by Christine Ammer.

hit the sack

INFORMAL or

hit the hay

mainly AMERICAN, INFORMAL
If someone hits the sack, they go to bed. We were tired, so we only half-unpacked the car and then hit the sack. Do you want me to take you up to your bed? Are you ready to hit the hay? Note: In the past, people sometimes used sacks and hay as bedding.
See also: hit, sack
Collins COBUILD Idioms Dictionary, 3rd ed.

hit the hay

go to bed. informal
See also: hay, hit

hit the sack

go to bed. informal
See also: hit, sack
Farlex Partner Idioms Dictionary

hit the hay

and hit the sack
tv. to go to bed. Time to go home and hit the hay! Let’s hit the sack. We have to get an early start in the morning.
See also: hay, hit

hit the sack

verb
See hit the hay
See also: hit, sack
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

hit the hay/sack, to

Go to bed, go to sleep. The first expression dates from about 1900 and presumably alludes to a hayloft as a soft bed. A sports book of 1905 held it to be baseball players’ slang. The second term dates from World War II, although sack for “bed” originated in the U.S. Navy in the 1820s.
See also: hay, hit
The Dictionary of Clichés by Christine Ammer
See also:
  • hit the sack/hay
  • climb into (something)
  • bed down
  • bed down (some place)
  • bedding
  • in bed
  • make a bed
  • put (someone or something) to bed
  • put something to bed
  • put to bed