There are many different colour terms in most languages of the world. This study examines how English colour terms are used in an extensive computerised text corpus. Focusing on those occasions when a colour term may refer to peripheral nuances or may evoke meanings that are outside the colour domain, and employing the theoretical framework of cognitive linguistics, the study demonstrates that occurrences of peripheral meanings can be modelled on the present idea of the colour domain. Three types of usage are identified as the sources of "stretched" meanings: classifying usage, figurative usage and marked usage. The first two show similarities and are primarily restricted to the most basic colour terms, while the third shows that non-basic terms can be used to achieve markedness effects.

On the basis of the patterns of usage that can be established and the frequency of occurrences, this thesis suggests that the colour category may be analysed as a radial category, with the most basic terms forming the centre.