Metonymy-producing relationships
The idea that metonymy provides access to (or highlights a particular aspect of) a domain matrix leads to two closely related questions. Firstly, what common patterns of access are there? Secondly, what are good vehicles for access? We address the first of these questions in this section, and the second of these questions in section 9.6.3. Our discussion is based on the study by Kövecses and Radden (1998).
In their paper, Kövecses and Radden examine the kinds of relationships that give rise to the metonymies that occur frequently in language. They observe that there appear to be two main kinds of motivating relationships: (1) those relating to the part-whole organisation of a given domain (or domain matrix) so that parts (or substructures) of a domain represent the entire domain; (2) those involving parts of a domain that stand for other parts. These are illustrated below with just a few examples taken from the extensive taxonomy provided by Kövecses and Radden.

These examples illustrate that the part-whole structure of a domain provides a ‘route’ of access via metonymy. A whole entity can be accessed by a part, or a part can be accessed by the entire domain.
Domain part-part relationships
This type of metonymic relationship is illustrated here as it relates to the domain of ACTION which involves INSTRUMENTS, an AGENT, a PATIENT, an end RESULT and so on. These ‘parts’ or substructures within the domain of ACTION can be metonymically related, as the following examples from Kövecses and Radden (1998: 54–5) illustrate:

These examples from the domain of ACTION illustrate that a part of the domain can metonymically provide access to another part. Thus, together with the examples relating to part-whole structure of domains, these two sets of examples illustrate the ways in which metonymy provides access within a domain (or domain matrix).