The Collaborative International Dictionary of English v.0.48:

Sty \Sty\ (st[imac]), n.; pl. Sties (st[imac]z). [Written also
   stigh.] [AS. stigu, fr. st[imac]gan to rise; originally,
   probably, a place into which animals climbed or went up.
   [root]164. See Sty, v. i., and cf. Steward.]
   1. A pen or inclosure for swine.
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   2. A place of bestial debauchery.
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            To roll with pleasure in a sensual sty. --Milton.
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