ETYM Old Eng. twilight, as. twi- (see Twice) + leóht light; hence the sense of doubtful or half light; cf. lg. twelecht, German zwielicht. Related to Light.
1. A condition of decline following successes.
2. The diffused light from the sky when the sun is below the horizon but its rays are refracted by the atmosphere of the earth.
3. The time of day immediately following sunset; SYN. dusk, gloaming, nightfall, evenfall, fall.
Period of faint light that precedes sunrise and follows sunset, caused by the reflection of light from the upper layers of the atmosphere. The limit of twilight is usually regarded as being when the Sun is 18ş below the horizon. The length of twilight depends on the latitude—at the tropics, it only lasts a few minutes; near the poles, it may last all night.
Borough in Pennsylvania (USA).