'NSAID' originates from modern English, specifically the phrase 'nonsteroidal anti-inflammatory drug', formed by taking the initial letters 'N', 'S', 'A', 'I', 'D'.

The full phrase 'nonsteroidal anti-inflammatory drug' was coined in the mid-20th century to distinguish these medicines from steroidal anti-inflammatory agents; the abbreviation 'NSAID' became common in medical literature by the 1960s–1970s and is now standard usage.

Initially it referred to the descriptive phrase for drugs that are anti-inflammatory and not steroidal; over time the abbreviation 'NSAID' came to be used widely as the primary name for that class of drugs with essentially the same meaning.