Stereoscopes and Stereopticons - what the difference?

Stereopticon show from Art History

I see these words used interchangeably.

Stereopticon is special two-lamp magic lantern, that allows operator to have dissolves. It is not 3D.

Stereoscope is a viewer that allow you to look at two stereo pairs in 3D.

A very funny Stereoscope from the library news clippings

References

• Stereoscopes (wikipedia) view the two sided cards so they are 3D
• Stereopticon (wikipedia) is a slide projector, a fancy early one that could dissolve between slides...basically what powerpoint can do now for us.
• Good website with cross-eyed stereo views and alternate for those who can't do that.