<p><strong>Verb</strong></p><ul><li>(used with object) to discover or catch (a person) in the performance of some act: to detect someone cheating.</li><li>to discover the existence of: to detect the odor of gas.</li><li>to find out the true character or activity of: to detect a spy.</li><li>Telecommunications: to rectify alternating signal currents in a radio receiver.</li><li>to demodulate.</li></ul>