What is the definition for patient identifiable data?

In the US, the legally specified term is Individually Identifiable Health Information which, under HIPAA, is protected. Here is the text from the Privacy Rule, Definitions, section 160.103:

Individually identifiable health information is information that is

a subset of Health Information, including demographic information

collected from an individual, and:

(1) Is created or received by a health care provider, health plan, employer, or health care clearinghouse; and

(2) Relates to the past, present, or future physical or mental

health or condition of an individual; the provision of health care to an individual; or the past, present, or future payment for the provision of health care to an individual; and

(i) That identifies the individual; or

(ii) With respect to which there is a reasonable basis to believe the information can be used to identify the individual.