Definition of "champaign"

Thenne ſyre Gawayne was ſore greued with theſe wordes / and pulled oute his ſwerd and ſmote of his hede / And therwith torned theyr horſes and rode ouer waters and thurgh woodes tyl they came to theyre buſſhement / where as ſyr Lyonel and ſyr Bedeuer were houyng / The romayns folowed faſt after on horſbak and on foote ouer a chãpayn vnto a wood [...]Then Sir Gawain was sore grieved with these words, and pulled out his sword and smote of his head, And therewith turned their horses and rode over waters and through woods till they came to their bushment, where as Sir Lionel and Sir Bedivere were hoving, The Romans followed fast after on horseback and on foot over a champaign unto a wood [...]]

, book V (in Middle English), [London: […] by William Caxton], published 31 July 1485, leaves 85, recto – 85, verso; republished as H[einrich] Oskar Sommer, editor, Le Morte Darthur […], London: David Nutt, […], 1889, pages 169–170

Of all theſe bounds euen from this Line, to this, / With ſhadowie Forreſts, and with Champains rich'd / With plenteous Riuers, and wide-ſkirted Meades / We make thee Lady.

c. 1603–1606, William Shakespeare, “The Tragedie of King Lear”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene i], page 283, column 2

So Segrave in Leiceſterſhire (which Towne I am now bound to remember) is ſited in a Champain, at the edge of the Wolds, and more barren than the villages about it, yet no place likely yeelds a better aire.

1638, Democritus Junior for Henry Cripps, partition 2, section 2, member 3, page 261

Where the Red Lion ſtaring o'er the way, / Invites each paſſing ſtranger that can pay; / Where Calvert’s butt, and Parſon’s black champaign, / Regale the drabs and bloods of Drury-lane; [...]

a. 1775, Oliver Goldsmith, “A Description of an Author’s Bed-chamber”, in Poems and Plays. […], London: Messrs. Price [et al.], published 1785, page 10

They are ſeated alongſt the ſea-coaſt, encompaſſed toward the land with huge and ſteepie mountains, having betweene both, a hundred leagues or there abouts of open and champaine ground.

1603, Michel de Montaigne, “Of the Caniballes”, in John Florio, transl., The Essayes […], book I, London: […] Val[entine] Simmes for Edward Blount […], page 102

A fine champagne country, well stored with corn.

1751, [Tobias] Smollett, The Adventures of Peregrine Pickle […], volumes (please specify |volume=I to IV), London: Harrison and Co., […]

In England mobility was taken for granted, at least outside the champaign agricultural areas.

1972, Christopher Hill, The World Turned Upside Down, Folio Society, published 2016, page 35