A user name (usually written username) is the unique identifier you use to log in to a computer system, website, or app, often together with a password.

Simple definition

  • A user name is a sequence of characters that identifies you on a digital system (for example, an email service, social network, or forum).
  • It is usually unique in that system, so no two accounts share the same user name.
  • You typically type your user name plus a password to access your account.

What a user name does

  • Distinguishes your account from others on the same service (like a login ID or account name).
  • Can be visible to others (for example, your handle on a forum or social media), though some sites show a separate display name instead.
  • May also be an email address in some systems (for example, using your full email as the login name).

Small example

  • On a service like Twitter/X, the handle @freeCodeCamp is the user’s chosen user name on that platform.

If you meant “what is my user name on a specific site,” that’s something only you or that site can see; I don’t have access to your accounts.