The owner of a business will often use his own name as its business name - the name it trades with, eg John Smith for a sole trader, or London Washing Services Limited for a limited company.
However, many businesses trade under a separate business name instead. Larger partnerships invariably do this, because a business name made up of all the owners' names would be too long; but sole trader John Smith could also choose to trade as, eg Internet Solutions, and limited company London Washing Services Limited could trade as City Laundries.
Different trading names can be used for different parts of the same business. For example, a building firm might trade using one business name for its building division and another for its building supplies service.
A brand name used for a product or service is a business name too. For example, Microsoft uses the brand names Word, Excel, Access, Powerpoint, Outlook, etc for its software applications. When choosing a brand name the same considerations apply as when choosing any other business name.
