Hit the sack is an informal expression meaning to go to bed to sleep. Phrase Finder places it in the United States in the early twentieth century; the reviewed evidence in this wave is sufficient for that broad chronology but not for a precise first printed use or a proved single-origin story.
ReviewedEvidence2 sourcesSectionPhrases & Idioms
Quick answer
It means to go to bed, usually because you are ready to sleep.
Key details
Core Meaninggo to bed to sleep
Registerinformal
Reviewed HistoryUnited States, early 20th century
What the evidence supports
Supported
The idiom was in American use by the early twentieth century.
Phrase Finder summarizes the expression as US, early 20th century.
Not established
The phrase was coined specifically because early beds were literal sacks filled with material.
The reviewed sources support the meaning and broad chronology but do not establish a single documentary coinage mechanism.
Documented timeline
Date unresolved
US early-twentieth-century use
Phrase Finder places the idiom in the United States in the early twentieth century.
secondary reportedconfidence: medium
Variants
hit the sack
Current Cambridge form.
hit the hay
Cambridge lists hit the hay as a synonymous idiom.
Meaning over time
Modern sleep sense
Go to bed in order to sleep.
Further guidance
Meaning
Cambridge defines hit the sack, also hit the hay, as an informal way to say go to bed in order to sleep.
Origin boundary
this guide does not turn the intuitive “sack as bed” explanation into a proved coinage story because the reviewed source summary does not establish that chain directly.
Regional History
Phrase Finder labels the idiom as US, early twentieth century, while current use is widely understood beyond the United States.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
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