1. Photographic slides; transparent photographs mounted in frames for projection onto a screen.
Usage: Plural form; often used in educational and professional contexts.; More common in British English and technical/archival usage; 'slides' is the standard American term.

Examples

• The museum stored hundreds of diapositives from the 1960s in climate-controlled cabinets.
• The professor used diapositives to illustrate the lecture on Renaissance art.
• We digitized the old diapositives to preserve them for future generations.
• The collection of diapositives documented the architectural changes in the city over decades.
• Before digital projectors, diapositives were the standard tool for presentations.