Photography, slide.
A positive photographic image on transparent material (as glass or film)

ETYM AS. slîde.
1. A sloping chute down which children can slide.
2. The act of sliding or gliding; SYN. glide.
3. Flat rectangular piece of glass on which specimens can be mounted for microscopic study.
4. (Geology) The descent of a large mass of earth or rocks or snow etc.

A semi-transparent photographic image mounted in a frame, viewed with a slide projector; SYN. lantern slide.