1ac·id 
/ˈæsəd/ noun
plural acids /ˈæsəd/ noun 1 chemistry : a chemical with a sour taste that forms a salt when mixed with a base [count] ▪ the acids in your stomach [noncount] ▪ the kinds of acid found in your stomach ◊An acid has a pH of less than 7. Very strong acids are able to burn holes in things. — compare 1base 6, ph 2 [noncount] slang : lsd
▪ His friend dropped acid [=took LSD] at the concert.
▪ His friend dropped acid [=took LSD] at the concert.
