1911 Encyclopædia Britannica/Beetle
BEETLE (O. Eng. bityl; connected with “bite”), a name commonly applied to those insects which possess horny wing-cases; it is used to denote the cockroaches (q.v.) (black beetles), as well as the true beetles or Coleoptera (q.v.), the two belonging to different orders of Insecta.
The adjective “beetle-browed,” and similarly “beetling” (of a cliff), are derived from the name of the insect. From another word (O. Eng. betel, connected with “beat”) comes “beetle” in the sense of a mallet, and the “beetling-machine,” which subjects fabrics to a hammering process.