Acronyms are new words formed from the initial letters (or parts) of a series of words, such as RAM from random access memory, and radar from radio detecting and ranging. Initialisms are a similar sort of abbreviation but are pronounced by saying each letter separately, for example BBC, VHS, and the FYI of this post’s title. The distinction, BTW, is not always strictly observed – initialisms are often loosely called acronyms. This imprecision is rarely problematic, but it’s good to know the difference. HTH.