Action of a particular (frequently specified) kind; the production of a characteristic, predictable, or intended effect; functioning, operation. Now…

That which is done, or is intended or expected to be done, by a particular thing; that which anything is fitted to perform, or performs customarily…

Use, service, function. Obsolete.

The function or proper mode of operation of a limb, organ, etc. Cf. office, n. 4b. Now rare (in later use only in to refuse its (also their) service).

With possessive adjective or genitive. Office; function; service.

An activity or mode of operation that is proper or natural to a person or thing; the purpose or intended role of a thing.

In singular and plural. The functioning of a machine, organization, system, etc.; the way that a machine, organization, system, etc., operates. Also…