When evaluating a single group or company, its dominant source of revenue is typically used by industry class to classify within a specific industry. For example the International Standard Industrial Classification used directly through derived classifications for the official statistics of most countries worldwide classifies statistical units by the economic activity in which they mainly engage. industry then defined as set of statistical.

There are many industry classifications in the modern economy, which can be grouped into larger categories economic sectors. For example, the retail trade sector contains industries such clothing stores, shoe stores, a health Companies are not limited to one sector or industry. Sector are broader than industry classifications.