Medical vocabulary is complex, and convoluted not least because of large numbers of compound terms. Formalized medical terminologies such as SNOMED-CT and ICD-10 take one of two strategies when representing medical language: socalled pre-coordination where valid compound terms are included explicitly and post-coordination where the terminology consists of a basis and a generative function from which the compound terms may be derived. However, these notions are not used with particular precision. Here we provide a formalization of the notion of coordination, a technique for estimating the degree of coordination in a given system, and an examination, based on our technique, of the coordination level of a number of terminologies.