acids

Noun

acid (countable and uncountable, plural acids)

1. A sour substance.
2. Any compound which yields H+ ions (protons) when dissolved in water; an Arrhenius acid.
   • SE onset depends on a complex network of interactions among plant growth regulators, mainly auxins and cytokinins, during the proembryogenic early stages, and ethylene and gibberellic and abscisic acids later in the development of somatic embryos.2015 August 18, Clelia De-la-Peña et al., “The role of chromatin modifications in somatic embryogenesis in plants”, in Frontiers in Plant Science, volume 6, →DOI
3. Any compound that easily donates protons to a base; a Brønsted acid.
4. Any compound that can accept a pair of electrons to form a covalent bond; a Lewis acid.
5. Any corrosive substance.
   • You are in error. / This is terror. / This is your banishment. This land is mine. / This is what you earn. / This is the Law of No Return. / This is the sour dough, this the sweet wine. / This is my history, this my race / And this unhappy man threw acid in my face.2006, James Fenton, Jerusalem
6. (slang, uncountable) LSD, lysergic acid diethylamide.
   • In the end, though, there is one sure way to distinguish a real hippie from his assorted sympathizers: hippies drop acid. That is, real hippies frequently, if irregularly, ingest LSD.1967, Joe David Brown, editor, The Hippies, New York: Time, Inc, page 171

See all 10 meanings of acid