In computing, the term hard space has several meanings, all related to a special way of representing the white space between characters.
The most commonly used meaning is the same as nonbreaking space: a special space character used by a word processor that forbids an automatic line breaking (line wrap) at its position.
In earlier days of text editors that worked with text modeCRTdisplays, when a paragraph has to be justified, this achieved by means of inserting extra soft spaces at whitespaces. The soft spaces were called so because they could be "compressed" away during further editing. By contrast, ordinary spaces were called hard or incompressible spaces.
Also, in some older text editors, the hard spaces were both non-expandable (I.e., no soft spaces could be added to them.) and nonbreaking ones.
