correspondence-course (noun) correspondence course: educational course by mail, email, etc.
Sinonime: Cimmerian shade,
black, blackness, blackout, brownout, calignosity, cloudiness, crepuscule,
dark, dimness, dusk, duskiness,
eclipse, gloom, lightlessness, murk, murkiness, nightfall, obscurity, pitch darkness, shade, shadiness, shadows, smokiness, tenebrosity, twilight
Antonime: brightness, day, daylight, daytime, illumination, light, lightness, morning