noun
user ID; user identification
Computing term for a unique identifier assigned to a user, such as a username or numeric ID.
ログインするにはユーザーＩＤとパスワードが必要です。
You need a user ID and password to log in.
パスワード is the password used together with a user ID for authentication.
アカウント is the overall user account, while ユーザーＩＤ is the specific identifier within that account.
Loanword from English 'user ID', with 'ID' pronounced as アイディー.