white space

Short definition from Wiktionary

Noun

1. 1
   White area between written characters and graphic regions on a produced page or computer display; blanks and the vertical blank lines in between paragraphs, or other organized rows of text lines (poetry).
2. 2
   A contiguous collection of one or more characters that each represents horizontal or vertical space in typography.
3. 3
   Free time seen as an opportunity for gainful activity.