n. An abbreviation consisting of initial letters that are pronounced separately.
I find this to be an incredibly useful word that I came across a while ago. Despite the fact that it is particularly useful in helping with pronunciation, few people I’ve met know it.
Unlike a standard acronym, an initialism is spelled out when spoken. U.S.A. is an initialism while N.A.S.A. and SCUBA are not. Plenty of times, I have come across an acronym and had no idea how to pronounce it. Knowing whether or not it is an initialism solves the problem completely.