Voice command activation was a feature of vehicles that enabled them to be turned on by issuing verbal commands.
In 2371, Tom Paris noted that a 1936 Ford truck dated prior to the advent of voice command activation, necessitating a key to operate it instead. (VOY: "The 37's")
In 2267, Captain Kirk used voice command to order the computer to override all contrary instructions and to disengage the helm. (TOS: "The Menagerie, Part I")