3.2.3 Using the description and/or drawings to define unclear terms not defined in the claims 

Sometimes, the terms used to define claimed technical features are unclear and so the scope of the claims cannot be determined unambiguously. The search division then uses the description and/or drawings to interpret what these terms mean (see F‑IV, 4.2).

For example:

Claim 1: Pneumatic tyre comprising a wide groove disposed in a tread portion, characterised in that the wide groove is provided on the groove bottom with at least one longitudinal rib extending in the longitudinal direction of the wide groove.

Description: The term "wide", as used in the context of the present invention, means not less than 20mm wide.

The term "wide" in claim 1 is unclear because it is a relative term with no well-defined meaning in the technical field, and so the scope of the claim is also unclear (F‑IV, 4.6, Art. 84). However, the description unambiguously defines "wide" as meaning "not less than 20mm wide". The search division takes this definition into account during the search (and subsequently objects to the clarity of the term "wide" under Art. 84, second sentence, in the search opinion). The definition of "wide" in the description is also a fallback position (see B‑III, 3.2.5).