meso- + -lect
mesolect (plural mesolects)
- (linguistics) A variety of speech that is midway between the acrolect and the basilect.
- 1973 Sep, Derek Bickerton, The Nature of a Creole Continuum, in Language 49(3), page 642, 
- [...] one characteristic of the mesolect seems to be that it contains, not merely forms from the polar lects, but forms which in function, if not always in phonetic shape, are peculiar to itself.
between acrolect and basilect