Blanagram

A blanagram (from "blank"+"anagram") is a word which is an anagram of another but for the substitution of a single letter. The term has its origin in competitive Scrabble, where a blank tile on a player's rack may be used to form any of several possible words in conjunction with the player's other tiles.
Examples of blanagrams.
Many seven- and eight-letter words, such as KILOVOLT and QUIXOTIC, have no acceptable blanagrams; such words typically contain a subset of the letters JKQVWXZ.