6.1.7.1.4 Closed and Open Definitions and Implications for Interpretation

Date Published

The situation may arise where a specification includes a definition for a particular term/phrase but that definition is not limiting. For example, the claim is to a fish hook and the definition of fish hook is “a hook especially designed to catch trout” - this is a closed definition.  In contrast, if the definition of fish hook is “a hook especially designed to catch underwater creatures including but not limited to trout”, then this is an open definition.  Where a special meaning has an open definition and is therefore non-limiting, the ordinary meaning in the art is also invoked according to the hierarchy. In this situation, an explanation should be included to indicate why the ordinary meaning was also invoked.

The situation may arise where the specification includes a special meaning for a particular term/phrase which is closed but the examples or figures include matter outside the scope of that definition. The special meaning is still to be used to interpret the scope of the claim, as it would otherwise be regarded as importing gloss from the examples if a different interpretation was given.