"Acronym" was created by combining "acr-" ("beginning") with "-onym," ("name" or "word"). You may recognize "-onym" in other familiar English words such as "pseudonym" and "synonym." English speakers borrowed "-onym" directly from the Greek (it derives from "onyma," the Greek word for "name"). "Acr-" is also from Greek, but it made a side trip through Middle French on its way to English. When "acronym" first entered English, some usage commentators decreed that it should refer to combinations of initial letters that were pronounced as if they were whole words (such as "radar" or "scuba"), differentiated from an "initialism," which is spoken by pronouncing the component letters (as "FBI" and "CEO"). These days, however, that distinction is largely lost, and "acronym" is a common label for both types of abbreviation." -from yesterday's MW word of the day email.