former eastern German province, now southwestern Poland, from Latinized form of German Schlesien (Polish Śląsk), from the name of a river and a mountain there, from Silingi or Silingae, name of a Vandalic (Germanic) people who supposedly had a religious center at the mountain. Related: Silesian. In reference to cloth imported from there from 1670s, especially "a thin cotton cloth, commonly twilled, used for linings for women's dresses and men's garments."

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Definitions of Silesia from WordNet
silesia (n.)
a sturdy twill-weave cotton fabric; used for pockets and linings;
Silesia (n.)
a region of central Europe rich in deposits of coal and iron ore; annexed by Prussia in 1742 but now largely in Poland;
Synonyms: Slask / Slezsko / Schlesien