“Checkout” is a noun for the act, time, counter, or process of checking out. “Check out” is the verb, used for actions such as leaving a hotel, borrowing an item, paying for purchases, or examining something.
ReviewedEvidence1 sourceSectionEnglish Usage
Quick answer
Use “checkout” as the noun and “check out” as the verb.
Key details
Confusion Familyword-boundary
Rule Familyorthographic-boundary
Termscheckout, check out
Choose the right form
Decision table for Checkout vs. Check Out
If you mean / need
Use
Why
the place, time, process, or instance as a thing
checkout
It is the noun.
the action of leaving, borrowing, paying, or examining
check out
It is the verb.
Further guidance
Core difference
Write the noun as one word and the verb as two words.
Fast Test
If you can say “checked out” or “checking out,” use the two-word verb.
Sense Boundary
“Check out” has several established verb senses; the word-boundary rule follows grammatical role rather than a single meaning.
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.
Standard English writes “a lot” as two words for a large amount, number, frequency, or degree. “Alot” is a common misspelling in this sense; it should not be confused with the separate verb “allot.”
“Blackout” is the closed noun, while “black out” is the two-word phrasal verb. The verb can describe losing consciousness or obscuring/darkening something; the noun names the resulting event or state.
“Blowout” is a closed noun for several events or results, and Cambridge also records “blow-out” as a noun variant. “Blow out” is the two-word phrasal verb, including the sense of extinguishing a flame.
“Breakout” is a closed noun for an escape and an adjective in several established senses. Cambridge also documents “break-out” in modifier use. “Break out” is the two-word phrasal verb for meanings such as beginning suddenly or escaping.
“Breakthrough” is a closed noun for an important discovery or advance and can also modify a following noun. “Break through” is the two-word phrasal verb for forcing or moving through a barrier or threshold.
“Build up” is the two-word phrasal verb. For the noun, Cambridge records hyphenated “build-up,” while its American dictionary also records closed “buildup.” The noun spelling therefore has a documented regional/style variant rather than one universal form.
