Does a `+` in a URL scheme/host/path represent a space?

I am aware that a + in the query string of a URL represents a space. Is this also the case outside of the query string region? That is to say, does the following URL:

http://a.com/a+b/c

actually represent:

http://a.com/a b/c

(and thus need to be encoded if it should actually be a +), or does it in fact actually represent a+b/c?