← Dictionary

sign in

/saɪn ɪn/
IELTSAcademic
verb

To enter a computer, website, app, or system by giving your username and password. It can also mean to register your name on a list when you arrive somewhere.

  • Please sign in before using the app.
  • I signed in to my email account.
  • Guests must sign in at reception.

Adinary Nuance

Sign in is used for entering a system, account, or building. It is close to log in, but log in is more common in technical writing and older computer contexts. In everyday use, many people use both words the same way.

In other languages

Vietnamese
đăng nhập
Spanish
iniciar sesión
Chinese
登录
Japanese
サインイン
Korean
로그인

Etymology

“Sign in” became common in the 20th century with office systems and later computers. It combines “sign” and “in” to mean entering a record or account.

Common phrases

sign in to an accountsign in with Googlesign in at receptionsign in and out

Synonyms

Related words

Frequently asked questions

Is sign in the same as log in?
Yes, in everyday English they are very close. “Sign in” is often friendlier and more common on websites and apps.
Can I say sign into?
Yes. You can say “sign in to” a service or “sign into” an account in informal use.
What is the difference between sign in and check in?
“Sign in” is for accounts or systems. “Check in” is for hotels, flights, events, or arriving at a place.
Is sign in formal or informal?
It is neutral. You can use it in business, school, and everyday situations.