Definition of "afterpiece"

To preface much concerning these little after-pieces of Poetry, I hold needlesse, having spoke my mind so fully before.

1642, Henry More, Psychodia Platonica‎, Cambridge: Roger Daniel, Preface

The idea of farces, or after-pieces, tho’ an inferior branch of the Drama, is, in fact, among the refinements of an improved age.

1787, George Colman, “Notes on the Epistle to the Pisos”, in Prose on Several Occasions‎, volume 3, London: T. Cadel, page 96

There was a silly after-piece called Carnarvon Castle, or, The Birth of the Prince of Wales.

1793, James Boswell, in Danziger & Brady (eds.), Boswell: The Great Biographer (Journals 1789–1795), Yale 1989, p. 225

[…] let us have a play entire from beginning to end; so as it be a German play, no matter what, with a good tricking, shifting after-piece, and a figure-dance, and a horn-pipe, and a song between the acts.

1814 July, [Jane Austen], chapter XIII, in Mansfield Park: […], volume I, London: […] T[homas] Egerton, […], pages 257-258

The policeman, perceiving that the interest of the entire group of spectators was centred upon himself and Lorison […] was fain to prolong the situation—which reflected his own importance—by a little afterpiece of philosophical comment.

1910, O. Henry, “Blind Man’s Holiday”, in Whirligigs‎, New York: Doubleday, Page, page 273