What part of the plant does cumin come from?

Cumin is native to the Middle East and has been known from ancient times, in other Words there is presumed to be no specific date of discovery. More specifically, the Word is believed to be of Sumerian origin, where Sumer is an ancient Mesopotamian civilization dating back at least 6000 years. Mesopotamia was in the area between the Tigris and Euphrates rivers in present day Iraq.

(Adapted from the Wikipedia entries for "Cumin", "Sumerian", and "Mesopotamia")