I've been reading Code: The Hidden Language of Computer Hardware and Software by Charles Petzold, and he described the 5 basic gates (AND, OR, NAND, NOR, & XOR) with extreme clarity. In the chapter about adding machines, he described that we needed a gate that relays only when it receives a 0 and 0, or a 1 and 1 ("coincidence gate"). This is the exact opposite of an XOR gate, which relays only when it receives a 1 and 0, or a 0 and 1. I was wondering why we don't call the former gate a XAND ("exclusive and") gate? It makes perfect sense to me. It will only relay when it receives a 0 AND 0, or a 1 AND 1. It's just an AND gate that also relays with two 0s, but whenever I google "XAND" people say that it's not the correct term. Why not? and I'm sorry if this isn't in the right sub-forum, but I searched the forum for other logic gate threads and they all seemed to be located here.