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.
2. To discourse on; to handle in a particular manner, in
writing or speaking; as, to treat a subject diffusely.
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.
4. To negotiate; to settle; to make terms for. [Obs.]
To treat the peace, a hundred senators
Shall be commissioned. --Dryden.
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.
6. To subject to some action; to apply something to; as, to
treat a substance with sulphuric acid. --Ure.
7. To entreat; to beseech. [Obs.] --Ld. Berners.