| Noun | 1. | ECM - electronic warfare undertaken to prevent or reduce an enemy's effective use of the electromagnetic spectrum electronic warfare, EW - military action involving the use of electromagnetic energy to determine or exploit or reduce or prevent hostile use of the electromagnetic spectrum electronic deception - the deliberate use of electromagnetic energy in a manner intended to convey misleading information electronic jamming, jamming, jam - deliberate radiation or reflection of electromagnetic energy for the purpose of disrupting enemy use of electronic devices or systems |