• IPA: /ˈtɹiːtɪs/, /ˈtɹiːtɪz/

treatise (plural treatises)

1. A formal, usually lengthy, systematic discourse on some subject.
   • 1910, Emerson Hough, chapter I, in The Purchase Price: Or The Cause of Compromise, Indianapolis, Ind.: The Bobbs-Merrill Company, OCLC 639762314 ↗, page 0088 ↗:

     “ […] We are engaged in a great work, a treatise on our river fortifications, perhaps ? But since when did army officers afford the luxury of amanuenses in this simple republic ? […]”

   • 2005, Plato, Sophist. Translation by Lesley Brown. 232d.

     And if someone wants to know how to make objections to actual craftsmen themselves on the subject of art in general or any particular art, there are published treatises available, as you know.

• dissertation
• disquisition
• monograph
• treatment (informal explanation, usually in essay form)

• treat
• treaty

• French: traité
• German: Abhandlung, Traktat
• Italian: trattato
• Portuguese: tratado
• Russian: тракта́т
• Spanish: tratado