Overview of the Hierarchy

Date Published

The PCT GL stipulates a hierarchy by which terms or phrases are to be interpreted (paragraph 5.20):

i. If there is a special meaning (by explicit definition or otherwise, which equates to “dictionary definition”) use that meaning.

ii. If there is no special meaning, use the ordinary meaning (as understood in the technology by the person skilled in the art).

iii. If there is no ordinary meaning, use the everyday meaning (non-technical meaning).

Where there is a special meaning, then that meaning is given to the term or phrase. Where there is no special meaning, the ordinary meaning is used to understand the term or phrase. Where there is no special meaning and no ordinary meaning, the everyday meaning is used to interpret the term or phrase.

An underlying principle in claim interpretation relates to the person skilled in the art; terms and phrases in a claim are read by the person skilled in the relevant art, taking into account the priority date (see PCT GL 5.32 2nd sentence).

The PCT GL hierarchy is similar to claim construction in national examination where the plain meaning (everyday meaning) is used to construe terms, except where there is a well-recognised meaning in the art (ordinary meaning) or the meaning has a dictionary or explicit meaning in the application (special meaning). The principal difference between the PCT GL and construction in national examination is that the PCT GL does not permit any discretion as to the interpretation of the words with respect to the intent of the invention. See Rules of Construction for further information about construction of claims in national examination.