A machine was an apparatus which used energy to perform a function.
In 2373, Soleta discovered a machine which appeared to be trying to mind meld with her. At first she dismissed this as impossible, but then remembered that there was a precedent for this: Spock once mind melded with a machine called Nomad. (NF novel: Fire on High)
The natives of Kangus IV used a machine to simulate the destruction of their planet. (TNG novel: I, Q)