Your question is very vague but it could mean a few things. It could mean that the business is located in an English speaking country or that the business is inherently based on "English" such as an English language tutoring company.

Do you mean "Business English"? If so, that usually means the English language as used in international trade / business. A Business English course is usually quite similar to a normal (non-business) English course but more of the English vocabulary used in international trade will be taught than in a normal course and you may be taught some of the business customs in English-speaking countries too. If you did really mean "English business", "an English business" would mean a company based in England, while "English business" would mean business done in England, or something like that. However, I would need to see the whole sentence or paragraph you got this from before I could be sure.