A word ladder is a sequence of words of the same length in which each word is successively transformed into the next word by changing only one of its letters and not rearranging the other letters. For example, QUITE becomes SUITE by changing Q to S. The sequence could continue with SUITE to SPITE. SPITE to SPINE, SPINE to SPINS, SPINS to SPANS, and so on, theoretically continuing for hundreds of words. In the six words of this ladder from QUITE to SPANS, though, no letter-position is changed more than once (e.g., after Q has been changed to S in position 1, S remains in position 1 in each successive word). All the word ladders shown below follow this pattern of minimal changes, and they are thus known was minimal word ladders.
"Minimal Word Ladders,"
Word Ways: Vol. 21
, Article 14.
Available at: http://digitalcommons.butler.edu/wordways/vol21/iss2/14