sheath(redirected from medullary sheath, myelin sheath)
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1. Biology an enclosing or protective structure, such as a leaf base encasing the stem of a plant
2. the protective covering on an electric cable
A protective outside covering on a cable.
A space charge formed by ions near an electrode in a gas tube.
The metal wall of a waveguide.
(science and technology)
A protective case or cover.
In reinforced concrete, an enclosure which encases posttensioned tendons to prevent their being bonded during the placement of concrete.