What is the X in X-mas?
a game in which one player gave a word or line of verse to be matched in rhyme by other players. Thus, one said, "I know a word that rhymes with bird." A second asked, "Is it ridiculous?" "No, it is not absurd." "Is it a part of speech?" "No, it is not a word." This proceeded until the right word was guessed. Under the name of the ABC of Aristotle, crambo reportedly was played in England as early as the 14th century. It is frequently mentioned in the literature of the 17th and 18th centuries.