Another term for "tool" is instrument. This word is often used to describe a device or implement that is used to carry out a particular function, especially in contexts like music, medicine, or scientific research. For example, a stethoscope is a medical instrument, and a violin is a musical instrument.

Other synonyms for "tool" include:

1. Implement: Often used in agricultural or manual labor contexts, such as a gardening implement or a farming implement.
2. Device: A more general term that can refer to any piece of equipment or machinery designed for a specific purpose.
3. Apparatus: Typically used to describe a complex set of tools or equipment used for a specific task, often in scientific or technical settings.
4. Gadget: A colloquial term for a small, often innovative tool or device, usually with a specific function.
5. Utensil: Commonly used to describe tools used in cooking or eating, such as a kitchen utensil.
6. Contraption: A somewhat informal term for a mechanical device or tool, often implying something unusual or makeshift.
7. Appliance: Refers to tools or devices used in households, such as kitchen appliances like a blender or a toaster.
8. Mechanism: A term that emphasizes the mechanical nature of a tool or device, often used in engineering or technical contexts.
9. Gear: A more casual term, often used to refer to equipment or tools needed for a particular activity, such as camping gear or fishing gear.
10. Appurtenance: A more formal or technical term for an accessory or tool that is supplementary to a main device or system.

Each of these terms carries slightly different connotations and is used in specific contexts, but they all broadly refer to objects designed to perform a particular function or task.