Demai (Talmud) Wikipedia
Demai (Hebrew: דְּמַאי) is the third tractate of Seder Zeraim ("Order of Seeds") of the Mishnah and of the Talmud. There is some debate as to the literal meaning and origin of the word. It is concerned mainly with laws related to produce where it is suspected that ma'aser rishon (the first tithe for the Levi), terumat ma'aser and ma'aser sheini (the second tithe) or ma'aser ani (the tithe for the poor), depending on the year of the Shemittah cycle, have not been properly separated in accordance with Num. 18:24-28. It consists of seven chapters and has a Gemara from only the Jerusalem Talmud.