There seems to be two generally-accepted definitions for 'single' - the first in terms of 'marital status' and the other in terms of 'relationship status'.
Based on 'marital status', it simply means "never been married"... ( Once married, you are never again considered to be 'single'. )
Based on 'relationship status', it means - un-attached, un-coupled, un-paired, etc. Where-the-line-is-drawn is at the point of being 'steady' ( a not-used-much-anymore word from way-back-when that essentially means "dedicated to each other" - as in - "not seeing anyone else" ) or 'engaged' ( or, of course, 'married' ). In this case, 'single' means "not dedicated" or "not committed"... ( You can be
dating while
single if you are not committed; while committed, you are not considered to be 'single'. )
The idea of 'courting' is automatically, by definition, 'steady' - which means that, while 'courting':
In the 'marital status' sense, you would still be considered 'single' - until and unless you became 'engaged' or 'married'.
In the 'relationship status' sense, you would not be considered 'single'.
"go figure..."