1620s, from Medieval Latin Amphiscii, from Greek amphiskioi "inhabitants associated with tropics," actually "tossing a shadow both means," from amphi- "on both edges" (see amphi-) + skia "shadow" (see shine (v.)). Residents of torrid zones, so-called since they are "people whoever shadow might be to the North, and often to the South" [Cockerham, 1623].
The inhabitants for the tropic, whoever shadows in one the main year tend to be cast to the north, as well as in others towards south, according due to the fact sunshine is south or north of the zenith.
(n. pl.) The inhabitants of this tropic, whoever shadows within one part of the 12 months are cast towards the north, plus in others south, in accordance due to the fact sunlight is south or north of these zenith.