unit a chain, however, not a catena. The term catena was introduced later by Timothy Osborne and colleagues as a means of avoiding confusion with the preexisting chain concept of Minimalist theory. Since that time, the catena concept has been developed beyond O'Grady's analysis of idioms to serve as the basis for the analysis of a number central phenomena in the syntax of natural languages (e.g. ellipsis and predicate–argument structures). Idiosyncratic language Idiosyncratic language of all sorts can be captured in terms of catenae. When meaning is constructed in such a manner that does not allow one to acknowledge meaning chunks as constituents, the catena is involved. The meaning-bearing units are catenae, not constituents. This situation is illustrated here in terms of various collocations and proper idioms. Some collocations Simple collocations (i.e. the co-occurrence of certain words) demonstrate well the catena concept. The idiosyncratic nature of particle verb collocations provide the first group of examples: take after, take in, take on, take over, take up, etc. In its purest form, the verb take means 'seize, grab, possess'. In these collocations with the various particles, however, the meaning of take shifts significantly each time depending on the particle. The particle and take convey a distinct meaning together, whereby this distinct meaning cannot be understood as a straightforward combination of the meaning of take alone and the meaning of the preposition alone. In such cases, one says that the meaning is non-compositional. Non-compositional meaning can be captured in terms of catenae. The word combinations that assume non-compositional meaning form catenae (but not constituents): Both sentences a and b show that while the verb and its particle do not form a constituent, they do form a catena each time. The contrast in word order across the sentences of each pair illustrates what is known as shifting. Shifting occurs to accommodate the relative weight of the constituents involved. Heavy constituents prefer to appear to the right of lighter sister constituents. The shifting does not change the fact that the verb and particle form a catena each time, even when they do not form a string. Numerous verb-preposition combinations are idiosyncratic collocations insofar as the choice of preposition is strongly restricted by the verb, e.g. account for, count on, fill out, rely on, take after, wait for, etc. The meaning of many of these combinations is also non-compositional, as with the particle verbs. And also