What is the term for a sequence of letters that spells a word backwards and forwards, e.g., 'repaid' backwards is 'diaper'.
I know that a palindrome spells the same word backwards and forwards, but this is a different situation.
Can anyone help?

well, it's a type of anagram (reverse anagram?), for one...

-ron o.

but the *artificial term that's been coined for the concept is Semordnilap (palindromes reversed), a word or phrase that spells a different word or phrase backwards. link

That's clever! Who coined this artificial term? Teop? Reniocdrow?

Mitch