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1640s, "feeler or horn of an insect," from Latin antenna "sail yard," the long yard that sticks up on some sails, of unknown origin, perhaps from PIE root *temp- "to stretch, extend." In the etymological sense, it is a loan-translation of Aristotle's Greek keraiai "horns" (of insects). Modern use in radio, etc., for "aerial wire" is from 1902. Adjectival forms are antennal (1834), antennary (1836), antennular (1858).