a medieval glove, as of mail or plate, worn by a knight in armor to protect the hand.

a glove with an extended cuff for the wrist.

the cuff itself. ?

take up the gauntlet

to accept a challenge to fight

He was always willing to take up the gauntlet for a good cause.

to show one's defiance. Also, take up the glove.

throw down the gauntlet

to challenge.

to defy. Also, throw down the glove.

noun

armor , challenge , glove , onslaught , ordeal , test , trial