When it comes to the broad meaning of "instrument" in English vocabulary, it refers to a tool or device that is used for a particular purpose. However, there are several other words that can be used interchangeably with "instrument". For instance, the term "implement" can be used to mean a tool or piece of equipment used for a particular task or activity. Another synonym for the word "instrument" is "apparatus", which refers to a group of machines, equipment or tools that are used together for a specific purpose. Therefore, a machine, device, appliance, or gadget can be categorized as a synonym of "instrument" too.