An*ten"na (&?;), n.; pl. Antennæ (&?;). [L. antenna sail-yard; NL., a feeler, horn of an insect.] (Zoöl.) A movable, articulated organ of sensation, attached to the heads of insects and Crustacea. There are two in the former, and usually four in the latter. They are used as organs of touch, and in some species of Crustacea the cavity of the ear is situated near the basal joint. In insects, they are popularly called horns, and also feelers. The term in also applied to similar organs on the heads of other arthropods and of annelids.

• device to receive or transmit radio signals etc. by converting electromagnetic radiation into electrical signals
  
• feeler organ on the head of an insect, crab or other animal