ˈskaɪəpɒd

Skiapod or Sciapod: A mythological human with a single leg and large foot, used to provide shade in tropical regions

The existence of skiapods was common knowledge in Classical times—they are mentioned by Aristophanes in his play The Birds, and by Pliny the Elder in his Natural History, in which the are described as inhabiting India.

The name comes from the Greek skia, “shadow”, and the pod combining form of pous, “foot”, that I’ve talked about already. So the skiapods were “shadow feet”. Makes sense. You can use the word skiapodous or sciapodous to refer to anyone with large feet.

The skiapods were just one of many races of imaginary types of person who populated the remote corners of the Classical and Mediaeval world. The Nuremberg Chronicle also provides illustrations of the Blemmyae (who had no heads, but faces in their chests) and the Panottii (who had large ears they could use instead of clothing).

Greek skia, “shadow”, produced a lot of words, but you have to go digging to find them. Skiagraphy or sciagraphy is “shadow drawing”, and it seems to have had a number of meanings over the years. It has been applied to that complicated part of perspective drawing that involves accurately rendering shadows:

But it also has been used for the drawing of silhouette portraits, for the making of X-ray images, to refer to any sort of rough sketch (presumably because the sketch  foreshadows the final version),  and for the telling of time using  shadows—that is, by sundials (of which, more later).

Skiamachy or sciamachy is “shadow fighting”: either literal shadowboxing (for training in combat sports), or metaphorical fighting with imagined enemies.

An antiscian is a person whose shadow points in the opposite direction to yours: someone on the same meridian  but in the opposite hemisphere. (Strictly, that only works properly outside the tropics.) I’ve waited all my life for a chance to use that word, but the occasion doesn’t come up very often.

A macroscian is a person with a long shadow; not usually a tall person, but instead one who lives at high latitudes, where the sun is always low in the sky. A periscian also lives at high latitudes, but specifically within one of the polar circles. The word means “all-around shadow”, and if you live within one or other of the polar circles there will be at least one day of the year on which the sun never sets, and your shadow will sweep right around you during the course of the day.

An ascian has no shadow. The word designates someone who lives in what was called the Torrid Zone when I was at school—between the Tropic of Cancer and the Tropic of Capricorn. Anywhere in that region there will be two days a year when the sun is directly overhead at noon, and people appear to cast no shadow. The word amphiscian means “both-sides shadow”, and also designates the folk in the Torrid Zone, who (on every day but an “ascian” day) may see the sun either to the north or south at noon, and who therefore can cast shadows in either direction at that time.

That’s the inhabitants of the polar and torrid zones dealt with. What about those in the temperate zones? They’re heteroscians—”different shadows”. In the temperate zones, the direction of your shadow at noon is always the same—it points north in the northern hemisphere, and south in the southern hemisphere. People in the two zones are therefore always heteroscian to each other: their noon shadows point in opposite directions. So the word should really be used by one bunch of people, in one temperate zone, to talk about the other bunch of people in the other temperate zone. But instead it’s applied loosely to all the inhabitants of temperate zones, presumably because someone felt the need to come up with some sort of shadow-based nomenclature to match periscian and amphiscian.

While these are fine linguistic curiosities, they say important things about the world. Since shadow directions at noon are always opposite in the two temperate zones, but the sun always progresses across the sky from east to west, shadows sweep in opposite directions as the day progresses in the two zones: clockwise in the north, anticlockwise in the south.

So for the purposes of skiagraphy, sundials need to be numbered in different directions, according to which side of the equator they’re on: