1. One of the principal rivers of Russia, rising in the Sayan Mountains in Mongolia, near the lake Khubsugul (Höbsögöl), flowing northward, being joined by the Angara and then by the Stony or Lower Tunguska, and reaching the Arctic Sea in the west of the Taymyr National Okrug.

2. Also, a Siberian language, alternatively known as Ket, Yeniseian, or Yenisei-Ostyak. It has only a few thousand speakers.

It is an isolate, that is it is not known to be related to any other language. There are a number of these scattered across Siberia, and they are sometimes termed Palaeo-Siberian, but this falsely implies that they are related to each other. Some linguists think they can see a distant affinity of Ket with the Sino-Tibetan languages.

There were formerly a number of other languages in the area, related to Ket, but they have died out. Together they may be termed the Yeniseian family. Their names are: Kott, Yug, Arin, Assan, and Pumpokol.