Sour, sharp, or biting to the taste; tart; having the taste of vinegar: as, acid fruits or liquors. Also fig.: Sour- tempered.
- Chemistry Any of a class of substances whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals to form salts.
- Chemistry A substance that yields hydrogen ions when dissolved in water.
- Chemistry A substance that can act as a proton donor.
- Chemistry A substance that can accept a pair of electrons to form a covalent bond.
- A substance having a sour taste.
- The quality of being sarcastic, bitter, or scornful: wrote with acid about her first marriage.
- Slang See LSD1.
- Chemistry Of, relating to, or containing an acid.
- Chemistry Having a high concentration of acid.
- Chemistry Having the characteristics of an acid.
- Having a pH of less than 7.
- Having a relatively high concentration of hydrogen ions.
- Geology Containing a large proportion of silica: acid rocks.
- Having a sour taste. See Synonyms at sour.
- Biting, sarcastic, or scornful: an acid wit; an acid tone of voice.