These pages comprise a dictionary of terms relating to the pipe organ. Please keep definitions to a few sentences, and do not include pictures or sound clips. When more space is needed for a term, a new page can be created for it. Labial [adj.] labial pipes are flue pipes. Ladegast, Friedrich (1818-1905) - German Romantic organ builder, studied with Cavaillé-Coll. Languid [noun] a thick metal disk which separates the body of a flue pipe from the foot, tightly soldered to both except for a flattened portion at the mouth which, along with the lower lip, forms the windway. Lead Leather Lower Lip