Dictionary.net

Applied to the inhabitants of the torrid zone who are shadowless at noon. They are also called amphiscii, because when not shadowless their shadows will at noon fall northwards one part of the year and southwards at another. The inhabitants of the N. temperate zone at noon have their shadows always falling northwards, and those of the s. Temperate zone always south, and are called antiscii. In the frigid zones, when the sun is above the horizon, the shadows of the inhabitants are directed to every point of the compass in succession, and they are called periscii.