“Readout” is the closed noun for displayed or produced information, especially from equipment. “Read out” is the two-word phrasal verb meaning to say written words aloud.
ReviewedEvidence2 sourcesSectionEnglish Usage
Quick answer
Use “readout” as a noun for information produced or displayed by equipment. Use “read out” as a phrasal verb when someone reads words or numbers aloud.
Key details
Confusion Familyword-boundary
Noun Variant ScopeCambridge records closed “readout” as a noun and “read out” as a phrasal verb.
Rule Familyorthographic-boundary
Termsreadout, read out
Choose the right form
Decision table for Readout vs. Read Out
If you mean / need
Use
Why
information or a display produced by equipment
readout
Cambridge records the closed noun.
the action of saying written words or numbers aloud
read out
Cambridge records the phrasal verb as two words.
Further guidance
Core difference
Use the documented noun or modifier form when naming a thing, result, event, or concept; use the spaced form when the words function as a verb.
Fast Test
If the expression can take ordinary verb tense or inflection in the sentence, the spaced verb form is usually the relevant choice.
Variant Boundary
Cambridge records closed “readout” as a noun and “read out” as a phrasal verb.
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.
