Time Zone vs. Timezone
In ordinary edited prose, “time zone” is the standard open noun. Google’s style guide likewise uses “time zone” as a noun and “time-zone” attributively; closed “timezone” is common in technical identifiers but should not automatically replace the ordinary noun.
Use “time zone” as the ordinary noun in prose. A technical product, field name, or code identifier may use “timezone,” so follow the relevant system when naming it exactly.
Key details
Choose the right form
| Context | Use | Decision |
|---|---|---|
| ordinary prose noun | time zone | Use the standard open form. |
| attributive style where the house guide calls for it | time-zone + noun | Follow the documented style convention. |
| literal API field, database column, product label, or code symbol | preserve its exact identifier | Do not normalize technical names to prose spelling. |
Quick tests
Prose-or-identifier test
Are you writing the ordinary noun in running prose?
If yes: Use “time zone.”
If no: If you are naming a literal technical identifier or product field, reproduce that system’s exact spelling.
Caveat: Closed “timezone” is common in technical identifiers, but that does not make it the default ordinary-prose noun.
Examples
The meeting crosses three time zones.
The ordinary noun is written as two words.
Check the time-zone setting in the style example.
The hyphenated attributive form follows the documented style-guide pattern.
The API returns a field named timezone.
A literal technical identifier keeps the system’s own spelling.
Further guidance
Core difference
Dictionary and style-guide evidence supports the open noun “time zone.”
Usage Boundary
Distinguish normal prose from literal technical identifiers. When quoting an API field, database column, product label, or code symbol, preserve that system’s exact spelling.
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.
- Time zone — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Dictionary evidence for the open noun time zone
- Google developer documentation style guide: word list (opens in a new tab)Google · House-style evidence for time zone as noun and time-zone as adjective