A·cous·tic a.  Pertaining to the sense of hearing, the organs of hearing, or the science of sounds; auditory.
 Acoustic duct, the auditory duct, or external passage of the ear.
 Acoustic telegraph, a telegraph making audible signals; a telephone.
 Acoustic vessels, brazen tubes or vessels, shaped like a bell, used in ancient theaters to propel the voices of the actors, so as to render them audible to a great distance.


 Ves·sel, n.
 1. A hollow or concave utensil for holding anything; a hollow receptacle of any kind, as a hogshead, a barrel, a firkin, a bottle, a kettle, a cup, a bowl, etc.
    [They drank] out of these noble vessels.   --Chaucer.
 2. A general name for any hollow structure made to float upon the water for purposes of navigation; especially, one that is larger than a common rowboat; as, a war vessel; a passenger vessel.
    [He] began to build a vessel of huge bulk.   --Milton.
 3. Fig.: A person regarded as receiving or containing something; esp. Script., one into whom something is conceived as poured, or in whom something is stored for use; as, vessels of wrath or mercy.
    He is a chosen vessel unto me.   --Acts ix. 15.
 [The serpent] fit vessel, fittest imp of fraud, in whom
 To enter.   --Milton.
 4. Anat. Any tube or canal in which the blood or other fluids are contained, secreted, or circulated, as the arteries, veins, lymphatics, etc.
 5. Bot. A continuous tube formed from superposed large cylindrical or prismatic cells (tracheae), which have lost their intervening partitions, and are usually marked with dots, pits, rings, or spirals by internal deposition of secondary membranes; a duct.
 Acoustic vessels. See under Acoustic.
 Weaker vessel, a woman; -- now applied humorously.  “Giving honor unto the wife, as unto the weaker vessel.” --1 Peter iii. 7. “You are the weaker vessel.”