Pet names

"Hypocorism" was once briefly a buzzword among philologists who used it rather broadly to mean "adult baby talk," that is, the altered speech adults use when supposedly imitating babies. But what the Greeks likely had in mind with their word "hypokorisma" was simply pet names: diminutives like our "Johnny" for "John," endearing terms such as "honey-bunch," or names from baby talk, like "Nana" for "Grandma." "Hypokorisma" comes from the verb "hypokorizesthai" ("to call by pet names"), which itself comes from "korizesthai" ("to treat with tokens of affection"). English speakers borrowed the noun as "hypocorism" (by way of Late Latin "hypocorisma") in the late 19th century. Once the baby talk issue faded, "hypocorism" settled back into being just a fancy word for pet name.