Analemma

Part of speech: noun

Pronunciation: /ˌæn.əˈlɛm.ə/

Definitions

1. A graphical illustration that represents the sun's varying position in the sky over the course of a year as seen from a specific geographic point
2. A two-dimensional plot demonstrating the sun's path in the heavens as observed from a fixed location across all seasons
3. A figure formed by plotting the sun's position at the same time annually from a fixed observation point on Earth

Etymology: The Greek word "análēmma" originally meant the pedestal or support on which a sundial was mounted, built from "ana-" (up) and "lēmma" (something taken or received). The sense then shifted from the physical stand to the figure the sun's position traces out. Over a year, if you photograph the sun at the same clock time on the same day each month from one spot, its positions form a figure-eight shape, and that curve is what astronomers now call the analemma. The shift makes sense once you see the link. A sundial's base was the solid thing the dial rested on, and the chart of the sun's yearly wandering, plotted against the dial's markings, became the new object of that name. The word thus moved from a stone support to a diagram of the sun's path across the sky, the same shape you can see when you record it over a year.