MIKE MOSS SAYS: Gail, While most of us nowadays think of the word meteor in association with the streaks of light produced by particles from space falling into our atmosphere, the word comes from the Greek "meteoron" which more or less meant "something in the sky." Meteorologists study many phenomena that include the word meteor, although these terms are not typically used in common speech. For example, clouds, fog, snow crystals, rain drops and so on are all "hydrometeors," literally water in the air. Suspended dust, sand, soil, soot, salt crystals and other dry particulates are known as "lithometeors," while corona discharges and lightning (visible results of electrical discharges in the air) are classed as "igneous meteors" and a more broadly defined term for effects of electrical discharges (including the invisible, but audible thunder) is "electrometeors." Finally, there is also the term "optical meteors," which includes phenomena such as rainbows, halos, glories, mirages, coronae and other such atmospheric displays.