Why Do They Call It Chickenpox? I've heard that question more times than I can count this week. I haven't been able to come up with a definitive answer. (I guess that's why the question keeps getting repeated.) Some say it's to distinguish it from smallpox - in which the bumps are bigger. (That was my first answer - a complete guess. He didn't buy it.) Some say it's because it is a pox that primarily affects children ("chicks"), and others say it's because the rash looks like chickpeas (Least likely. Were chickpeas common in the West when the word "chickenpox" came about?) The American Heritage Dictionary favors the first explanation, as do these language mavens.