1. A device or implement, especially one held in the hand, used to carry out a particular function.
2. A distinct design in the tooling of a book.
3. Impress a design on (leather, especially a leather book cover).
4. Equip or be equipped with tools for industrial production.
Plural noun: Tools.
Verb forms: Tool, Tooled, Tooled.
Computers are an essential tool.