Each CPC definition, whether it is a subclass, main group, or subgroup definition, must adhere to the same definition template which defines the permissible elements and formatting. Most CPC schemes will include supplementary definitions to clarify the scope of classification places as well as to inform the user of special classification rules in that area. Definitions are provided for CPC subclasses, main groups or subgroups, but not for CPC sections or classes. Not all CPC subclasses or groups have definitions. When a title is sufficiently clear to describe the scope of the classification place, a definition statement is not necessary.
A definition may include the following:
- (A) Definition title – The definition title always reflects the title of the classification place being defined. For example, a subclass definition will have the same title as the title of the subclass; a group definition will have the same title as the title of the group.
- (B) Definition Statement – The scope of the definition statement should essentially be the same as the scope of the title. The definition statement should clearly elaborate the meaning of the classification place rather than merely restating its title. The definition statement should provide a positive description of the subject matter appropriate for the classification place, rather than a negative description of the subject matter excluded from the classification place. The appropriate classification places for the excluded subject matter are found under “Limiting References”.
- (C) References relevant to classification in a subclass/group
- (1) Limiting and precedence references – See MPEP § 905.01(a)(1).
- (2) Specially adapted references – Specially adapted references are references from function-oriented (general) to application-oriented places. The subject matter indicated by a specially adapted reference could be classified in the instant classification place, and in the classification place where the reference points to, or both.
- (3) Residual references – Residual references from residual subclasses (defined as such in the title of the subclass or the definition statement) to non-residual places should appear in this section.
- (4) Informative references — Informative references are references that indicate the location of subject matter that could be of interest for searching, but are not within the scope of the classification place where the reference occurs. References from application-oriented places to function-oriented places are informative.
- (D) Special rules of classification within the subclass/group — This section contains special classification rules, which apply only within the subclass/group and not between subclasses/groups. Examples of such classification rules are the first place or the last place priority rules.
- (1) First place priority rule: When a document is classifiable in more than one group in a scheme, the one highest in the scheme is allocated to the document.
- (2) Last place priority rule: When a document is classifiable in more than one group in a scheme, the one lowest in the scheme is allocated to the document.
- (3) Common rule: When a document is classifiable in more than one group in a scheme, the classification symbol that most completely covers the invention is allocated to the document.
- In CPC, as with IPC, in the absence of any classification rule, common rule, defined in (D)(3) above, is the governing classification rule.
- (E) Glossary of terms — This section consists of definitions for significant words or phrases found in the titles or definition statements. Terms found exclusively in patent documents or in technical literature, but not in the scheme or the definition statement, will normally appear in the synonyms and keywords section.
- (F) Synonyms and Keywords – This is an optional section establishing synonyms, keywords, abbreviations and acronyms from terms used in the patent documents themselves or in technical literature. This section aids in formulating search queries in electronic searching in the technical field. This section may include definitions of such terms when they do not appear in the scheme or the definition statement.