tester

One who tests, tries, assays, or proves.

Any instrument or apparatus used in testing.

A name given to the shillings coined by Henry VIII., and to sixpences later (compare teston); also, in modern slang, a sixpence.

A canopy.

Specifically— The frame which connects the tops of the posts in a four-post bedstead, and the material stretched upon it, the whole forming a sort of canopy.