Morphology is the study of word formation and structure. In synthetic languages, a single word stem (for example, love) may have a number of different forms (for example, loves, loving, and loved).However, for some purposes these are not usually considered to be different words, but rather different forms of the same word.

Word ladder (also known as Doublets, word-links, change-the-word puzzles, paragrams, laddergrams, or word golf) is a word game invented by Lewis Carroll.A word ladder puzzle begins with two words, and to solve the puzzle one must find a chain of other words to link the two, in which two adjacent words (that is, words in successive steps) differ by one letter.