From Longman Dictionary of Contemporary Englishscroll barˈscroll bar noun [countable] a part on the side of a computer screen that you move using a mouse in order to move up or down
Examples from the Corpus
scroll bar• A scroll bar with up and down arrows above and below lets you move through the contents.• A scroll bar, called the timeline, lets you grab information by date.From Longman Business Dictionaryscroll barˈscroll bar noun [countable]COMPUTING the thin bar at the edge of a computer screen with which you move information on the screen up or down, using a mouse 