Short Definition
A set of buttons or icons grouped in a user interface that provides quick access to frequently used tools or functions, such as file operations or formatting options in applications like word processors or browsers.
Relevance
Toolbars are a set of buttons or menus that give quick access to common actions in a program or website. They’re important for learning to use screen-based software because they help users find and use key tools more easily.
Further Reading
https://en.wikipedia.org/wiki/Toolbar