It is likely a unique family name that may have been spelled differently over time or within different branches of the family.
If you are trying to find someone with this last name, it might be helpful to try searching for variations on the spelling. For example:
* Keater
* Keateria
* Keteria
* Cateria
* Keatery
You could also try searching for the name along with other information you have, like a first name or location.