Economic activity is understood as referring to a process, that is to say, to the combination of actions carried out by a certain entity that uses labour, capital, goods and services to produce specific products (goods and services).

An activity is characterized by (a) an input of resources; (b) a production process; and (c) an output of products.

By convention, a single activity is understood as a process resulting in a homogeneous type of product. It is recognized that one activity may consist of one simple process or may cover a whole range of sub-processes, each of which might be classified in a different activity category.

International Recommendations for Industrial Statistics, 2008 (IRIS 2008)