Which word means corresponding in size, degree, or extent?

The word "commensurate" is accurate for describing a relationship where two things correspond in size, degree, or extent. When something is described as commensurate, it implies a direct comparison or balance, meaning that one entity is aligned or equivalent to another in a measurable or quantifiable way. This term is often used in contexts like salaries, responsibilities, or any situation where a fair and proportional relationship is established based on certain criteria.

In contrast, while "proportional" might suggest a relationship involving ratios, it doesn't convey the specific idea of equal value or measure as strongly as "commensurate." "Equivalent" denotes having equal value but isn’t necessarily tied to the idea of measurement alongside another. "Similar" indicates likeness or resemblance but lacks the direct correlation in size or degree that "commensurate" encapsulates. Therefore, "commensurate" provides the clearest and most precise meaning in this context.