"Turn the key" is a common phrase that refers to the action of starting or stopping a mechanical or electrical device by turning a key. However, there are several other synonyms that can be used to convey the same meaning. Examples include "insert the key," "twist the key," "ignite the engine," "activate the ignition," "power on," "engage the mechanism," or "switch on/off." Each of these synonyms can be used interchangeably with "turn the key" and will convey the same message, depending on the context and the intended audience. So the next time you need to instruct someone to start or stop a device, try mixing it up with one of these synonyms for a more diverse and engaging conversation.