Sign-in vs. Sign In
“Sign-in” is documented by Collins as a hyphenated noun in American English, while “sign in” is the two-word phrasal verb in Cambridge. Product-interface labels can follow house style, so the page keeps that regional/style boundary explicit.
Use “sign-in” as the hyphenated noun for an act or time of signing in in the Collins American-English entry. Use “sign in” as the phrasal verb, such as “Please sign in at reception.”
Key details
Choose the right form
| If you mean / need | Use | Why |
|---|---|---|
| an act, instance, or time of signing in | sign-in | Collins records this hyphenated noun in American English. |
| the action of registering arrival or entering account details | sign in | Cambridge records the phrasal verb as two words. |
Further guidance
Core difference
Use the documented noun or modifier form when naming a thing, result, person, 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
Collins records the hyphenated noun “sign-in” in American English, while Cambridge records “sign in” as the phrasal verb; interface labels may still follow product house style.
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.
- sign in — definition and meaning (opens in a new tab)Collins English Dictionary · Hyphenated sign-in noun in American English and sign in verb phrase
- sign in — English meaning (opens in a new tab)Cambridge Dictionary · Two-word phrasal verb sign in for registering arrival or entering account details