- a curved wire inserted into the undersides of the cups of certain bras for increased support
- such a brain full underwire bra
- A semicircular wire support sewn into the underside of each cup of a brassiere.
- A brassiere with such a wire support.
(third-person singular simple present underwires, present participle underwiring, simple past and past participle underwired)
- To fix such a wire in place