Other forms: waistcoats
A waistcoat is a sleeveless buttoned top worn under a jacket. A three-piece suit with waistcoat, unbutton the waistcoat, a tweed waistcoat.
The convention is to leave the bottom button undone, which is said to date from a king who was too stout to fasten his. It is the American vest, and vest in Britain means an undershirt, which causes constant confusion between the two countries.
1nounwaistcoatA sleeveless buttoned top worn under a jacket.
“For the wedding, he wore a grey suit with a matching waistcoat.”
waistcoat is a garment.
Waist plus coat, from the seventeenth century, when the garment reached only to the waist.
From waist + coat. Compare yol wauscoat, wazcoote.
Etymology from Wiktionary, CC BY-SA