Definition of "spencer"

In order to support and illustrate this assertion, I shall commence my remarks with the spencer, which has often been attacked by satyrical and cynical writers as an absurd and original dress.

1799, D.D., “To the Editor”, in The Scots Magazine, volume 61, page 677

To have seen Miss Squeers now, divested of the brown beaver, the green veil, and the blue curl-papers, and arrayed in all the virgin splendor of a white frock and spencer, with a white mulsin bonnet, and an imitative damask rose in full bloom on the inside thereof;

1799, Sir Francis d' Ivernois, Historical and Political Survey of the Losses Sustained by ..., page 97

Some wear the tunic of lawn, and the spencer or Turkish robe of silk.

1800, “Parisian Fashions”, in The Lady's Magazine, page 254

I am seized with an angry resentment against the conventions of twenty years ago, which wrapped up my comely adolescent body in woollen combinations, black cashmere stockings, “liberty” bodice, dark stockinette knickers, flannel petticoat and often, in addition, a long-sleeved, high-necked, knitted woollen “spencer”.

1933, Vera Brittain, Testament of Youth, Penguin, published 2005, page 34