Guide to construction

Special meanings

2.37 When interpreting the words in a claim, one should initially assume that the words take the meanings they would ordinarily have been given by the person skilled in the art at the time of the invention. If a term is given a special meaning by the author, this needs to be taken into account (Kirin-Amgen Inc. v Roche Diagnostics GmbH [2002] RPC 1). A general approach would be to consider:

(1) Does a term in a claim have a plain meaning to the person skilled in the art?

(2) Does the context in which the term is used in the specification change the meaning of the term?

(3) Does the specification impose a special meaning on the term?

2.38 For example, if the claim defines “a crane hook comprising features X, Y and Z”, the plain meaning would impart a particular shape in the form of a hook and certain limitations on the size of the hook. If the specification provided a special meaning “as used herein the term crane hook is taken to mean a sling hook” then the claim would be interpreted as being a sling hook and not, for example, a ramshorn hook (a double hook used in cranes for lifting heavy loads). If this special meaning was not given, then the term would most likely be read as including any type of crane hook, unless, for example, the person skilled in the art would read the invention as only being a particular type of crane hook because of the features defined or the context.

2.39 Generally, if the specification provides a special meaning for a particular term, it should, as far as possible, be clear from the wording of the claim alone that the term is defined in such a manner (T 1568/06 Methods for improving damaged retinal cell function/Optobionics Corporation). This applies for example when a claim contains terms where the special meaning given to the terms deviates from what the skilled person would understand the terms to mean. If it is unclear what meaning a particular term in a claim is supposed to take on, then a clarity objection may be raised.

2.40 A reference in the claim such as the phrase “as hereinbefore defined” can indicate that the term is limited to a special meaning previously defined in the description or in an earlier claim. This should not be confused with the use of similar phrases in omnibus claims (see Section E in Chapter 5), which would not be allowable under Rule 19(9)

2.41 Moreover it should be clear from the specification that the special meaning given to the term is the only intended meaning. This will be obvious from phrases such as:

“as used herein, the term alkyl means C1 to C5 straight or branched chain alkyl …”.

If the term is defined in a less definite manner then it should not be considered a special meaning. Some of these non-limiting phrases are:

“suitable elastomers include …”

“the elastomers may be …”

“The term elastomeric includes but is not limited to …”

2.42 If a special meaning is indicated in one part of the description but there is departure from that meaning in another part, then the special meaning should not be given when interpreting the claims.