Password

A string of characters (letters, numbers, and other symbols) used to authenticate an identity or to verify access authorization. 

See the following under Password for more information: 
NIST SP 800-12 Rev. 1 (FIPS 140-2). 
NIST SP 800-82 Rev. 2. 
 
 A string of characters (letters, numbers and other symbols) that are used to authenticate an identity or to verify access authorization. A passphrase is a special case of a password that is a sequence of words or other text. In this document, the use of the term “password’ includes this special case. 

See  NIST SP 800-133 under Password for more information. 
 
  A string of characters (letters, numbers and other symbols) that are used to authenticate an identity, to verify access authorization or to derive cryptographic keys. 

See the following under Password for more information: 
NIST SP 800-57 Part 1 Rev. 4. 
NISTIR 7621 Rev. 1 (NIST SP 800-57 Part 1 Rev. 3). 
 
 A protected/private string of letters, numbers, and/or special characters used to authenticate an identity or to authorize access to data. 

See NSA/CSS Manual Number 3-16 (COMSEC) for more information. 
 
 Confidential authentication information, usually composed of a string of characters. 

See ISO DIS 10181-2 for more information.