Questions regarding regional variants of the Chinese language

topolect is defined as:

A set of similar dialects constituting any of the larger distinct regional varieties of a language.

For example, Mandarin Chinese is a topolect that includes the dialects of Beijing and Nanjing, and is distinct from Hakka, another topolect of Chinese. [topo- + (dia)lect (translation of Chinese (Mandarin) fāngyán, regional speech : fāng, place + yán, language).]

Thus making it a more appropriate term for what are usually called 'dialects'.