Dark fringes refer to areas or edges that lack light or are shadowed. Synonyms for this phrase include "shaded borders," "obscured edges," "dim perimeters," "shadowy outlines," and "gloomy margins." Such terms are often used to describe physical features such as the dark fringes of a forest, the shaded borders of a garden bed, or the dim perimeters of a room. However, the expression may also be utilized in a metaphorical sense to denote a sense of mystery or foreboding - for example, dark fringes of the mind or the shadowy outlines of an unexplained phenomenon.