This thesis looks at conceptual combination, in particular it investigates how noun noun compounds are interpreted. Several themes run throughout the work. Real compounds (e.g. coat hanger, crab apple) are compared to novel ones (e.g. banjo cactus, zip violin). Also, compounds are examined in each of the possible permutations of artefacts (A) (e.g. coat, banjo) and natural kinds (N) (e.g. crab, cactus), (AA, AN, NA and NN).Experiments 1 - 4 examine noncompositionality in noun noun compounds. Possible sources of noncompositionality are investigated using both feature listing and feature rating tasks. Although some differences were found, results were similar between different types of compound, evidence of noncompositionality being found in each. The results also confirm that most of the meaning of a noun noim compound is derived from the second constituent (noun2).Experiments 5 and 6 look at two different types of compoimd interpretation - slot filling and property mapping. In experiment 5, slot filling is found to be the preferred interpretation type overall, but property mapping is more common in compounds composed of two natural kinds (NN). Experiment 6 examines possible factors influencing the choice between slot filling and property mapping interpretations. It was found that constituent similarity plays an important role, and also that this interacts with whether or not the constituents have important properties which clash. Experiment 7 looks at compound identification. Results suggest that the first constituent (nounl) may be critical in such tasks. Experiment 8 compares the importance of nounl and noun2 in determining the type of interpretation given to a compound. Neither position is found to be more influential than the other, although relational information does seem to be associated with specific nouns in each position. Throughout the thesis findings are related to current theories of conceptual combination, such as prototype models, the concept specialisation model and theories of compound interpretation by analogy.