The Old Norse male name Ketill is widely used across the Scandinavian world, including the Viking diaspora. It is also common as an element in compound names such as Grímketill (in later times usually appearing in a reduced form as Grímkell) or Ketilbjörn. In place-names it occurs for example in Kedleston, Derbyshire, Ab Kettleby, Leicestershire and several names in Lincolnshire such as Ketsby and Kettlethorpe.

The name is identical to the common noun ketill meaning ‘kettle, cauldron’, which is a loan-word from Latin catillus (a ‘small basin’ or ‘bowl’) in Germanic languages. This suggests it was originally a by-name and there are many suggestions as to how such a by-name might have come about, including because someone had a head shaped like a cauldron, or wore a cauldron-shaped helmet, or engaged in ritual activities using a cauldron. In any case, by the Viking Age it is well established as a given name, without obvious reference to its meaning.

The element is frequent in the Danelaw, both as a name and as the first element of place-names. Occasionally, the place-names may contain the Old English cognate cetel/cietel/cytel, used topographically for a deep valley surrounded by hills, and often associated with springs or streams. Its use as a personal name, however, seems to have been introduced by the Scandinavians.