D defs.my
Entry 3 senses Webster, 1913

Muscovite

/mŭs'-kəv-ītˌ/ · Mus·co·vite · IPA /ˈmʌs.kəˌvaɪt/
01 n. A native or inhabitant of Muscovy or ancient Russia; hence, a Russian.
  1. 1.
    A native or inhabitant of Muscovy or ancient Russia; hence, a Russian.
  2. 2.
    An inhabitant of Moscow.
  3. 3.
    Common potash mica, essentially KAl3Si3O10(OH)2. It is used as an electrical insulator. See Mica.(Min.) See: Mica