hair space
Noun
Meaning
(printing) the narrowest of the spaces used to separate words or letters
Source: WordNetHypernyms
Examples
As the online curly hair space expanded in the new millennium, many forum members began sticking to the ones that best fit their personal demographics.
Recently, however, that notion has been turned on its head as more skin-care brands have decided to dabble in the hair space.
MARTIN: Let's move into the hair space here.