Triadic patents are a series of corresponding patents filed at the European Patent Office (EPO), the United States Patent and Trademark Office (USPTO) and the Japan Patent Office (JPO), for the same invention, by the same applicant or inventor.
A set of three patents, one for each of the major patent offices - the EPO, USPTO, and JPO - are filed simultaneously to protect the same invention by the same person. These are known as triadic patents.