cardigan n : knitted jacket that is fastened up the front with buttons or a zipper

Colloquially speaking, cardigans are a rather "uncool" garment, favoured by old men, girls and the muesli / quiche eating, sandal wearing Pascal programming community.

See also, 2CV - the favoured car of said groups.

Cardigans are, in fact, named for the seventh Earl of Cardigan, James Thomas Brudenell. This particular Earl of Cardigan is also the Earl of Cardigan who lead the Charge of the Light Brigade during the Crimean War,memorialized in the poem by Tennyson, but the man himself, one of the charge's few survivors, is mostly remembered for his choice of sweaters.