The Acid Tests were a series of parties held by author Ken Kesey in the San Francisco Bay Area during the mid-1960s, centered entirely around the use of, and advocacy of, the psychedelic drugLSD, also known as "acid." LSD-25 was not made illegal until late in 1968.
Acid test (gold), a chemical or metallurgical test that uses acid, now also a general term for verified, approved, or tested in a large number of fields
Quick ratio, also known as acid-test ratio or acid-test liquidity ratio, a measure of a company's cash liquidity