space bar

noun

1. a horizontal bar on a typewriter keyboard that is depressed in order to resume typing one space to the right.
2. a horizontal bar on a computer keyboard that is depressed in order to move the cursor one space to the right or, often, to perform some function in a program.

space-bar

noun

1. a horizontal bar on a typewriter that is depressed in order to leave a space between words, letters, etc

Word History and Origins

Origin of space bar¹

First recorded in 1885–90