What is the X in X-mas?
1891, short for Martini cocktail (1886), perhaps from Martini & Rossi, Italian firm that makes vermouth (an ingredient of the drink); the firm was in existence then by that name, but it is not specified among the ingredients in the earliest recipes (e.g. Harry Johnson's "Bartender's Manual," 1888). Another theory holds that it is a corruption of Martinez, California, town where the drink was said to have originated. See discussion in Lowell Edmunds' book "Martini, Straight Up" (1998).