antenna

1. An appendage used for sensing on the head of an insect, crab, or other animal. [from 17th c.]Examples: "The overall shape of most insect antennae is elongate and cylindrical, although elaborations into plumose, lamellate, or pectinate forms have arisen many times in different insect lineages."; "He put his fingers over his head like two antennas, crossed his eyes, and waggled his tongue like some kind of insect. In the same work, Brown uses antennae to refer to both aerials and feelers during more technical descriptions."; "The basis of these relationships lies in the olfactory chemoreceptors of insect antennas..."Synonyms: feeler, feeler

2. (figurative) The faculty of intuitive astuteness.Examples: "Most nurses believe they are born with an antenna of sorts, which is able to guide them through clinical practice and help them determine what is right and what is not..."; "Obama is astute. He approaches things with the help of a sensitive antenna."Synonyms: clairvoyance, acumen, perspicacityfiguratively

3. (biochemistry) A fragment of an oligosaccharide

4. (nautical) The spar to which a lateen sail is attached, which is then hoisted up the mast.Synonyms: yard