Definify.com
Webster 1913 Edition
Armil
Ar′mil
,Noun.
[L.
armilla
a bracelet, fr. armus
arm: cf. OF. armille
.] 1.
A bracelet.
[Obs.]
2.
An ancient astronomical instrument.
☞ When composed of one ring placed in the plane of the equator for determining the time of the equinoxes, it is called an equinoctial armil; when of two or more rings, one in the plane of the meridian, for observing the solstices, it is called a solstitial armil.
Whewell.