The Collaborative International Dictionary of English v.0.48:

Treat \Treat\, v. t. [imp. & p. p. Treated; p. pr. & vb. n.
   Treating.] [OE. treten, OF. traitier, F. traiter, from L.
   tractare to draw violently, to handle, manage, treat, v.
   intens. from trahere, tractum, to draw. See Trace, v. t.,
   and cf. Entreat, Retreat, Trait.]
   1. To handle; to manage; to use; to bear one's self toward;
      as, to treat prisoners cruelly; to treat children kindly.
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   2. To discourse on; to handle in a particular manner, in
      writing or speaking; as, to treat a subject diffusely.
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   3. To entertain with food or drink, especially the latter, as
      a compliment, or as an expression of friendship or regard;
      as, to treat the whole company.
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   4. To negotiate; to settle; to make terms for. [Obs.]
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            To treat the peace, a hundred senators
            Shall be commissioned.                --Dryden.
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   5. (Med.) To care for medicinally or surgically; to manage in
      the use of remedies or appliances; as, to treat a disease,
      a wound, or a patient.
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   6. To subject to some action; to apply something to; as, to
      treat a substance with sulphuric acid. --Ure.
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   7. To entreat; to beseech. [Obs.] --Ld. Berners.
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