waistcoat

noun

1. An ornamental garment worn under a doublet.
2. (British)A sleeveless, collarless garment worn over a shirt and under a suit jacket.

   “Sunning himself on the board steps, I saw for the first time Mr. Farquhar Fenelon Cooke.[…]A silver snaffle on a heavy leather watch guard which connected the pockets of his corduroy waistcoat, together with a huge gold stirrup in his Ascot tie, sufficiently proclaimed his tastes.”

   “In the Victorian Era, exposing your shirtfront in public was considered improper, as shirts were viewed as undergarments. Waistcoats concealed this and helped [to] tame oversized, billowy shirts.”