Trea″tise (?), n. [OE. tretis, OF. treitis, traitis, well made. See Treat.] 1. A written composition on a particular subject, in which its principles are discussed or explained; a tract. Chaucer.
He published a treatise in which he maintained that a marriage between a member of the Church of England and a dissenter was a nullity. Macaulay.
☞ A treatise implies more form and method than an essay, but may fall short of the fullness and completeness of a systematic exposition.
2. Story; discourse. Shak.