The time period when the sun has dropped 6 degrees beneath the western horizon; it is the instant at which there is no longer sufficient light to see objects with the unaided eye. Light intensification devices are recommended from this time until begin morning civil twilight. Also called EECT.
END EVENING CIVIL TWILIGHT
Meaning of END EVENING CIVIL TWILIGHT in English
DOD English dictionary of military terms. Английский словарь военных терминов DOD. 2012