Definitions:

1. A shortened form of a word or phrase used to represent the whole. NOUN
   • In medicine 'BP' is an abbreviation for 'blood pressure'.
2. A way to represent a longer term by using fewer letters or symbols. NOUN
   • The abbreviation 'Mr.' is commonly used instead of 'Mister'.
3. Shortening something by omitting parts of it. NOUN
   • In texting, 'LOL' is an abbreviation for 'laughing out loud'.
4. The act or result of shortening or reducing. NOUN
   • The scientific paper included a list of abbreviations used throughout the text.

Synonyms:

• acronym
• condensation
• initialism
• short form
• shortening