#\Space
or else non-graphic characters such as #\Newline
that only move the print position.
2. a. n. the syntax type of a character
that is a token separator.
For details, see Section 2.1.4.7 (Whitespace Characters).
b. adj. (of a character)
having the whitespace[2a] syntax type2.
c. n. a whitespace[2b] character.