contrabass
Synonym discussion
Sense: noun/1
These words usually name the same large string instrument, but they appear in different situations. Double bass is the broadest term and works well in classical, school, and general music talk. Upright bass is common when speakers want to contrast the instrument with an electric bass guitar, especially in jazz or pop settings. String bass is also understood, but it can sound older or more American in school music programs. Contrabass is the most technical label and often appears in formal writing, catalogues, or instrument lists. A teacher might say, "Please tune the double bass before rehearsal," while a repair shop form might list the same instrument as a contrabass.
Etymology
Contrabass came into English through Italian contrabbasso. The first part means "against" or "opposite," and the second means "low," so the word originally described a bass instrument that sounds even lower than another bass instrument.