'To throw down the gauntlet' definitions:

Definition of 'To throw down the gauntlet'

From: GCIDE

Gauntlet \Gaunt"let\, n. [F. gantelet, dim. of gant glove, LL. wantus, of Teutonic origin; cf. D. want, Sw. & Dan. vante, Icel. v["o]ttr, for vantr.]
1. A glove of such material that it defends the hand from wounds. [1913 Webster]
Note: The gauntlet of the Middle Ages was sometimes of chain mail, sometimes of leather partly covered with plates, scales, etc., of metal sewed to it, and, in the 14th century, became a glove of small steel plates, carefully articulated and covering the whole hand except the palm and the inside of the fingers. [1913 Webster]
2. A long glove, covering the wrist. [1913 Webster]
3. (Naut.) A rope on which hammocks or clothes are hung for drying. [1913 Webster]
To take up the gauntlet, to accept a challenge.
To throw down the gauntlet, to offer or send a challenge. The gauntlet or glove was thrown down by the knight challenging, and was taken up by the one who accepted the challenge; -- hence the phrases. [1913 Webster]