Məsjosak [sic] (m)
(with) definite article: deHeard in Ronse and Kwaremont (both in prov. East-Flanders); NB: Spelling in Boone, according to whom "this is undoubtedly a variant of the Picardian name Muchosac".
Boone, Hubert: De doedelzak. Woord vooraf door J. Van Haver en A. Doppagne… Inleiding door R. De Maeyer… Brussel, 1983, p.15.