Which word describes a substantial relationship between two things?

The term "commensurate" is defined as being of equal measure, proportionate, or having a substantial relationship between two things. In various contexts, when two elements are said to be commensurate, it indicates that they correspond with each other in a way that is meaningful and significant. For example, one might say that the salary of a job is commensurate with the level of experience required, suggesting a direct and substantial correlation between the two.

In contrast, the other options do not convey the idea of a substantial relationship. "Archaic" refers to something that is very old or outdated and does not imply any connection between two contemporary elements. "Discordant" denotes a lack of harmony or agreement, suggesting a relationship characterized by conflict rather than substantiality. "Discrete" means separate or distinct, indicating a division rather than a relationship between two things. Therefore, "commensurate" is the most appropriate choice to describe a substantial relationship.