Pronunciation: ' är-m ə - ˌ ler- ē -, är- ' mi-l ə -r ē -
Function: noun
Etymology: French sphère armillaire, from Medieval Latin armilla, from Latin, bracelet, iron ring, from armus shoulder ― more at ARM
Date: 1664
: an old astronomical instrument composed of rings showing the positions of important circles of the celestial sphere