shield

(shéld). 1. Any protecting tube. 2. The metal tube that covers the core of soft iron in the primary coil of a faradic battery; by sliding or drawing it the current is intensified or diminished at will. Buller’s s., a watch-gla fitted over the eye to guard it from gonorrheal or ophthalmic infection. embryonic s., the dark circular field due to cell-proliferation within the area pellucid a, in which the primitive streak appears. nipple-s., a cover to protect the nipple of a nursing woman. phallic s., a device for the antiseptic protection of the male genitals during surgical operations.