This thesis addresses two fundamental issues regarding lexis in the Business English environment. It firstly asks whether the lexis of Business English is significantly different from that of 'everyday' general English, and secondly, if the lexis found in Business English published materials is significantly different from that found in real-life business. In order to test these hypotheses two corpora were created to form the basis of the analysis: the Published Materials Corpus (PMC) consisting of 33 published Business English course and resource books at 590,000 running words and the Business English Corpus (BEC) at, 1,023,000 running words divided between spoken (44%) and written (56%) texts. The BNC Sampler corpus was used as reference corpus. These three corpora were then able to be lexically compared by using WordSmith 3 (Scott 1999) using statistically-based key words. The results of these analyses showed that it was possible to define the world of business lexis, and also how it was lexically separated from general English by placing the words into a limited group of semantic categories. These categories were found to recur across word class boundaries and showed a lexical world of business bounded by its people, institutions, activities, events and entities, The boundary limits of business lexis were placed by the non-business lexis of the negative key words and the semantic groups they formed. Representative words from each of the main semantic groups were chosen for further study to see how they behaved both semantically and grammatically. Louw's (1993) concept of semantic prosody was used to determine how Business English words associated with certain semantic groups, and Firth's (1957) and Hoey's (1997) idea of colligation was used to show which grammatical patterns the words typically formed themselves into. Results of these secondary analyses of the BEC showed that whilst some business lexis associates with semantic groups unique to itself, most lexis is formed into patterns of interrelated semantic groups which regularly co-occur with each other. Additionally, there was evidence to suggest that words form associations to some semantic groups when in the business environment, and others when out of it. In the business setting, the meaning potential of words was found to be reduced and this had consequences both semantically and grammatically. Fewer meanings were used than in general English - and, as grammatical patterning and meaning were found to be co-dependent, restricted meaning led to area-specific and restricted grammatical patterning. The same analytical methods were used in the analysis of the PMC and it was compared both to the BNC, to see how published materials differ from general English, and to the BEC, to see how two corpora, both purporting to be Business English, differed from each other. Where the BEC could be seen to show a limited and specialist lexis, the PMC was even more limited. The lexical world of business presented by the materials showed a stress on personal and interpersonal contact, and a focus on a limited number of business activities, notably entertaining, travel, meetings and presentations. There was less reference to states and qualities, and the lexis in the PMC concentrated even more than the BEC on tangible, concrete items