An acronym is a word formed from the initial letters of other words.
For example:
The word scuba is an acronym of self-contained underwater breathing apparatus.
Other types of abbreviation like USA (for United States of America) are often considered to be acronyms as well these days, even though we pronounce them as separate letters.
We use a great many acronyms and abbreviations in English without even realising it.
Let's have a look at some!