It's a common word in Welsh place names, often combined with other words to describe the location, such as:
* Cae'r Gors: "The field of the bog"
* Cae'r Llyn: "The field of the lake"
* Cae'r Fferm: "The field of the farm"
It can also be used in more general contexts, like talking about a field of crops or a field where children play.