The x symbol in Boolean algebra means an intersection of two classes. An intersection of two classes is everything that is in both the first class and the second class. For example, F x T represents the class of all cats that are both female and tan. As in conventional algebra, we can write F x T as F·T or simply FT (which is what Boole preferred). You can think of the two letters as two adjectives strung together: “female tan” cats.
