the.com/angle grinder

means A handheld power tool fitted with a rotating abrasive disc, used for cutting, grinding, and polishing metal, stone, and other tough materials.

from Named simply and literally: the tool spins its disc at an angle to the handle/motor housing (via an angled gear drive), unlike a straight grinder where the disc sits in line with the motor shaft. 'Angle' here is pure mechanical description, not metaphor — the gearbox bends the rotational force roughly 90 degrees to drive the disc. The design traces to early-to-mid 20th-century industrial grinding tools, refined and popularized as portable versions arrived for workshop and construction use.