\Flue pipe\ (Music)
A pipe, esp. an organ pipe, whose tone is produced by the
impinging of a current of air upon an edge, or lip, causing a
wave motion in the air within; a mouth pipe; -- distinguished
from {reed pipe}. Flue pipes are either open or closed
(stopped at the distant end). The flute and flageolet are
open pipes; a bottle acts as a closed pipe when one blows
across the neck. The organ has both open and closed flue
pipes, those of metal being usually round in section, and
those of wood triangular or square.