The term (also in the nutritional sense) might be derived from Medieval Latin dieta, meaning both "parliamentary assembly" and "daily food allowance", from earlier Latin diaeta, possibly from the Greek διαιτησία ("arbitration"),[1] or transcribing Classical Greek δίαιτα (diaita), meaning "way of living", and hence also "diet" (regular food), "regular (daily) work".
[citation needed] Through a false etymology, reflected in the spelling change replacing ae with e, the word "diet" (diaeta) came to be associated with Latin dies, "day".
[2] The association with dies is reflected in the German language's use of Tagung (meeting) and -tag, meaning "day", as in Montag (Monday) and also "parliament", "council", or other legislative chamber, as in Bundestag or Reichstag for national parliaments, and Landtag for regional assemblies.
[3] In this sense, it commonly refers to the Imperial Diet assemblies of the Holy Roman Empire: After the Second Peace of Thorn of 1466, a German-language[citation needed] Prussian diet Landtag was held in the lands of Royal Prussia, a province of Poland in personal union with the king of Poland.
The Swiss legislature was the Tagsatzung (French: Diète) before the Federal Assembly replaced it in the mid-19th century.