Shutdown vs. Shut Down
“Shutdown” is a one-word noun for an occasion when a business, system, or machine stops operating. “Shut down” is the two-word phrasal verb for causing or undergoing that stop.
Use “shutdown” for the noun and “shut down” for the verb.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| a stoppage, closure, or process of stopping operations | shutdown | Use the closed noun. |
| the action of stopping a system, service, machine, or organization | shut down | Use the two-word phrasal verb. |
| a modifier before another noun | shutdown + noun | The closed form can function attributively where the noun sense is intended. |
Quick tests
Meaning / construction test
Is the expression functioning as the action verb?
If yes: Use “shut down.”
If no: Use “shutdown” when you mean the noun or its attributive use.
Caveat: The distinction is primarily word class; context still determines the exact sense.
Examples
The server will shut down after the backup finishes.
“Shut down” is the phrasal verb.
The factory announced a temporary shutdown.
“Shutdown” is the noun.
They reviewed the shutdown procedure.
The closed form modifies “procedure.”
Further guidance
Core difference
A system can “shut down,” while the event itself is a “shutdown.”
Fast Test
If tense works—“shut down yesterday,” “shutting down now”—you are using the two-word verb.
Variant Boundary
The core distinction here is grammatical role: noun versus 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.
- SHUTDOWN — English meaning (opens in a new tab)Cambridge Dictionary · One-word noun “shutdown”
- SHUT (SOMETHING) DOWN — English meaning (opens in a new tab)Cambridge Dictionary · Two-word phrasal verb “shut down”