An invertible symmetric-key cryptographic algorithm that operates on fixed-length blocks of input using a secret key and an unvarying transformation algorithm. The resulting output block is the same length as the input block.
Source(s):
NIST SP 800-107 Rev. 1 under Block cipher

  A family of functions and their inverse functions that is parameterized by cryptographic keys; the functions map bit strings of a fixed length to bit strings of the same length.
Source(s):
NIST SP 800-135 Rev. 1 under Block cipher
NIST SP 800-38A under Block Cipher

  An algorithm for a parameterized family of permutations on bit strings of a fixed length.
Source(s):
NIST SP 800-38B under Block Cipher

  A parameterized family of permutations on bit strings of a fixed length; the parameter that determines the permutation is a bit string called the key.
Source(s):
NIST SP 800-38D under Block Cipher
NIST SP 800-38F

  A symmetric-key cryptographic algorithm that transforms one block of information at a time using a cryptographic key. For a block cipher algorithm, the length of the input block is the same as the length of the output block.
Source(s):
NIST SP 800-90A Rev. 1 under Block Cipher