[tshaddox]

In computing it is widely used as a single word "whitespace." For example:

- The XML W3C Rec: https://www.w3.org/TR/xml/

- The HTTP 1.0 RFC: https://tools.ietf.org/html/rfc1945

However, there are exception. The Unicode character database has a property called "White_Space" which implies it is two words: http://www.unicode.org/reports/tr44/#White_Space

[nanis]

> a property called "White_Space" which implies it is two words

<tongue-in-cheek> Except that `_` is a "word" character by default. </tongue-in-cheek>