In dictionary entries, what does the abbreviation adj. mean? Adjective. It is an English dictionary abbreviation like adv. > adverb. You can abbreviate a long word by writing the first part of the word. An abbreviation is a shortened form of a word. In a dictionary, abbreviations are listed and explained as entries and are useful because it needs to squeeze a lot of writing into a small space.
Some readers may not know what an abbreviation means. So, make sure to explain what it means the first time you use it.