Baretti: A dictionary of the English and Italian languages
Móstr-a, s. f. dim. Móstr-étta,
1. show, appearance, apparent, but not real, importance; 2. mark, sign, token. Questo cavallo non ha — d'esser buono, this horse does not appear to be a good one; 3. example, pattern, sample of any thing;4. place in a shop where goods are kept in order to be seen; 5. a show-glass; 6. ostentation, parade, show; 7. dial-plate of a watch or clock, a watch. Dar —, to show, exhibit; 8. the facings of a uniform, livery, &c.; 9. muster, review of an army. Dare —, to muster the soldiers.
Florio: a worlde of wordes, or most copious, dictionarie in Italian and English
mostra: a shew or view of any thing, any patterne or sight. Also the sacing of any thing. Also a Sunne-dyall. Also a watch that sheweth the houres Also a muster or mustering of souldiers. Also ostentation, bragging, or vaine-glorie.