“Rollout” is a noun for the introduction or first availability of a product, service, proposal, or information. “Roll out” is the two-word phrasal verb for carrying out that introduction.
ReviewedEvidence2 sourcesSectionEnglish Usage
Quick answer
Use “rollout” for the noun and “roll out” for the verb.
Key details
Confusion Familyword-boundary
Noun Variant ScopeCambridge distinguishes the closed noun “rollout” from the two-word phrasal verb “roll out.”
Rule Familyorthographic-boundary
Termsrollout, roll out
Choose the right form
Decision table for Rollout vs. Roll Out
If you mean / need
Use
Why
the introduction or release of something
rollout
The noun is written as one word.
the action of introducing or making something available
roll out
The phrasal verb is written as two words.
Further guidance
Core difference
Use “roll out” when the expression functions as a verb; use the documented noun form for the person, thing, event, result, or modifier.
Fast Test
If tense or inflection works naturally—such as a past or -ing form—you are using the verb and should keep “roll out” as separate words.
Variant Boundary
Cambridge distinguishes the closed noun “rollout” from the two-word phrasal verb “roll out.”
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.
