Abbreviations and acronyms are shortened forms of words or phrases. What is an acronym? For one, acronyms are types of abbreviations. Acronyms are typically formed by using the first letter of each word in a phrase to form a new word. An acronym is an abbreviation used as a word which is formed from the initial components in a phrase or a word. Acronyms and abbreviations are both used to shorten a paragraph. Some types of abbreviations are acronyms (which are pronounceable), initialisms (using initials only), or.