crepusculum

As a noun crepusculum

is crepuscule; twilight; dusk.

As an adjective undefined is

lacking a definition or value.

As nouns the difference between dusk and crepusculum

is that dusk is a period of time occurring at the end of the day during which the sun sets while crepusculum is crepuscule; twilight; dusk.

As a verb dusk

is to begin to lose light or whiteness; to grow dusk.

As an adjective dusk

is tending to darkness or blackness; moderately dark or black; dusky.

As nouns the difference between twilight and crepusculum

is that twilight is the soft light in the sky seen before the rising and (especially) after the setting of the sun, occasioned by the illumination of the earth’s atmosphere by the direct rays of the sun and their reflection on the earth while crepusculum is crepuscule; twilight; dusk.

As an adjective twilight

is pertaining to or resembling twilight.