The term "edge" has multiple meanings and can be used in various contexts.
1) In a general sense, an edge refers to the boundary or limit between two things; for example, the edge of a cliff is where the land meets the sky.
2) In mathematics, particularly geometry, the term "edge" describes the line that separates two adjacent faces in a polyhedron (a solid with more than one face).
3) In computer graphics and design, an edge refers to the boundary between different colors or shades of color within an image.
4) In everyday language, the phrase "on the edge" means being at the brink of something; for example, someone who is on the edge of their seat may be very close to falling off it.
5) Finally, in a more slang sense, "edge" can refer to drugs or alcohol, particularly when used in the phrase "to take/do some edge."