A more thorough explanation:

Definition: A critical limitation is an essential requirement that must be met for an invention to work or for a patent claim to be granted.

Example 1: A critical limitation for a patent on a new type of engine may be that it must be able to produce a certain amount of power while meeting emissions standards. If the engine cannot meet these requirements, the patent claim may be rejected.

Example 2: A critical limitation for a patent on a new drug may be that it must be effective in treating a specific medical condition. If the drug does not meet this requirement, the patent claim may be rejected.

These examples illustrate how a critical limitation is an essential requirement that must be met for an invention to be successful or for a patent claim to be granted. Without meeting these requirements, the invention or patent claim may not be considered valid or useful.