(n.) the written notation of traditional dance steps
The fact that orchesography is a bizarre diagrammatic system for notating dance moves ended up one of last week’s most popular tweets:
So here’s a bit more about it. Both the word orchesography and this curious system of notation were invented by Thoinot Arbeau, a French Renaissance historian and scholar who wrote an influential treatise on French dances in 1577 called Orchésographie.
Arbeau based his word on two Greek roots: orkheisthai, meaning “to dance”, and graphe, meaning “to write” or “draw”. The second of these will be familiar as the root as words like geography (literally “a written description of the Earth”) and biography (“an account of life”), while the first is an etymological cousin of orchestra.
Long before it came to be used of the group of musicians who accompany a stage performance, an Ancient Greek orkestra was an open space or raised platform in front of a stage on which dancers or members of the chorus would perform.
From Arbeau’s work in the sixteenth century, orchesography was adopted into English in the early 1700s and has remained in (albeit fairly niche use) ever since.