a secret word or phrase known only to a restricted group
"he forgot the password"
A word used to gain admittance or to gain access to information; watchword.
"I can't give you my password, but I will tell you what it is if you promise not to write it down."
In plain English: A password is a secret code you type to prove who you are and get into an account.
"I forgot my password and cannot log into my account."
Usage: A password is a secret word or phrase required to log into an account or system. It functions as your unique key for verifying your identity before granting access.
To protect with a password.
"You can't access your account unless you set up a strong password to protect it."
In plain English: To password something means to protect it by setting a secret code that only you know.
"I need to password my new account before I can log in."
Usage: Although "password" can technically mean to secure something with a password, this usage is extremely rare and often sounds awkward in everyday conversation. It is much more natural to simply say you will "password protect" a file or "set a password" on an account instead of using the word as a verb directly.
The word password is a combination of "pass" and "word." Its original meaning referred to a phrase used by sentries to grant entry, which later inspired the modern use for secret codes in cryptography.