Definition of tester

• n. - A headpiece; a helmet.
• n. - A flat canopy, as over a pulpit or tomb.
• n. - A canopy over a bed, supported by the bedposts.
• n. - An old French silver coin, originally of the value of about eighteen pence, subsequently reduced to ninepence, and later to sixpence, sterling. Hence, in modern English slang, a sixpence; -- often contracted to tizzy. Called also teston.