The Collaborative International Dictionary of English v.0.48:
Treaty \Trea"ty\, n.; pl. Treaties. [OE. tretee, F. trait['e],
LL. tractatus; cf. L. tractatus a handling, treatment,
consultation, tractate. See Treat, and cf. Tractate.]
1. The act of treating for the adjustment of differences, as
for forming an agreement; negotiation. "By sly and wise
He cast by treaty and by trains
Her to persuade. --Spenser.
2. An agreement so made; specifically, an agreement, league,
or contract between two or more nations or sovereigns,
formally signed by commissioners properly authorized, and
solemnly ratified by the several sovereigns, or the
supreme power of each state; an agreement between two or
more independent states; as, a treaty of peace; a treaty
3. A proposal tending to an agreement. [Obs.] --Shak.
4. A treatise; a tract. [Obs.] --Sir T. Browne.