(historical) An apparatus for projecting upon a screen, by means of sunlight, an enlarged view of any object; essentially the same as the combination of lenses used in the magic lantern, taken in conjunction with a heliostat.

Synonym of sunspot

plural of solar spot

plural of solar microscope

The increase in thermal energy of a space, object or structure as it absorbs incident solar radiation.

plural of solar boat

(archaeology, Egyptology) A wooden burial boat intended to be used by a king to make celestial journeys in the afterlife.

Of an engine, vehicle, device, etc., deriving its energy from sunlight through the use of solar cells.

plural of solar cycle

(astronomy) The nearly periodic 11-year change in the Sun's activity, measured from a minimum of activity to the next.