Service

In general, a service is an action performed as an (intended) benefit to another individual person or to other persons, including other creatures, either voluntarily or as required by need.

In economics, a service is labor that can be bought or sold, as in professional advice. This is in contrast with a good. The entire market consists of goods and services.

At law, "service" refers to the delivery of notice of a lawsuit to the affected party, referred to as "service of process."

In psychology, self-serving persons act only to benefit themselves more than others, sometimes using others needs to serve their own selfish purposes, solely as a means of service to themselves alone for personal gain. Victims of such persons, after giving themselves in service to them, often come to realize that they have been "used".

See Mercenary.