Acronym

n. word formed from the first initials of several words (i.e. NASA)

Acronyms and initialisms are abbreviations, such as NATO, laser, and IBM, that are formed using the initial letters of words or word parts in a phrase or name. Acronyms and initialisms are usually pronounced in a way that is distinct from that of the full forms for which they stand: as the names of the individual letters (as in IBM), as a word (as in NATO), or as a combination (as in IUPAC). Another term, alphabetism, is sometimes used to describe abbreviations pronounced as the names of letters.
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Noun
1. a word formed from the initial letters of a multi-word name
(hypernym) form, word form, signifier, descriptor
(class) DINK

<jargon> An identifier formed from some of the letters (often the initials) of a phrase and used as an abbreviation. This dictionary contains a great many acronyms; see the contents page for a list.
See also TLA.
(1995-03-15)

a word formed from the first letter of a group of words e.g AIDA or SWOT; it is used as a memory aid.