A non-cryptographic definition of a permutation is "2a: the act or process of changing the lineal order of an ordered set of objects. 2b: an ordered arrangement of a set of objects
The Wikipedia article on Random permutation states that "A good example of a random permutation is the shuffling of a deck of cards: this is ideally a random permutation of the 52 cards."
An ideal block cipher is a pseudorandom permutation.
Shuffling a deck of identical cards would result in output indistinguishable from the input. Applying an ideal block cipher to an all-zero (or all-one) plaintext block would yield a random ciphertext block, not the same all-zero (or all-one) input block!
What's an easy-to-understand difference between a shuffle (equivalently a transposition cipher) and a permutation in the sense meant by cryptographers?