Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “acid”

acid

noun [C/U]  /ˈæs·ɪd/ us  
chemistry any of various chemical substances that can produce salts, some of which are able to damage whatever they touch

acid

adjective  /ˈæs·ɪd/ us  
sour in taste: The salad dressing has an acid taste. fig. An acid comment/remark is something said or written in strong criticism.
(Definition of acid from the Cambridge Academic Content Dictionary © Cambridge University Press)
What is the pronunciation of acid?
Browse related topics

You are looking at an entry to do with Specific types of drug, but you might be interested in these topics from the Drugs topic area:

Add Cambridge dictionaries to your browser to your website

Definitions of “acid” in other dictionaries

Word of the Day

roost

When birds roost, they go somewhere to rest or sleep.

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More