A quick definition of Prior art:

Term: Prior art

Definition: Prior art refers to all the information that is publicly available before someone claims to invent something. This information includes any existing patents, publications, or other materials that describe the invention. When someone applies for a patent, the invention must be novel and non-obvious. If the prior art contains a description of the supposed invention, it usually cannot be considered novel. Similarly, if the prior art contains enough information that the invention would have been obvious to someone with ordinary skills in the relevant field, a patent cannot be granted.

Example: If someone claims to have invented a new type of phone, but there are already patents or publications that describe similar phones, then the invention may not be considered novel. Similarly, if the invention is simply a combination of existing technologies that would have been obvious to someone with ordinary skills in the field, then a patent cannot be granted.