Tulane University defines an ore as a body of material from which one or more valuable substances can be extracted. For example, bauxite ore is mined and refined to extract aluminum.
root sheath the epidermic layer of a hair follicle. sheath of Schwann neurilemma. synovial sheath synovial membrane lining the cavity of a bone through which a tendon moves. tendon sheath a lubricated fibrous or synovial layer of tissue in which the tendon is housed and through which it moves.
Chambers 20th Century Dictionary(0.00 / 0 votes)Rate this definition: Sheath. shÄth, n. a case for a sword or other long instrument: a scabbard: any thin defensive covering: a membrane covering a stem or branch: the wing-case of an insect.âv.t.