Entry from OED Online

ploughman

SECOND EDITION 1989

ploughman's lunch, a cold snack, usu. including bread, cheese, and pickle, and freq. served in a public house at lunch-time; also ellipt., as plough-man's

[1837 J. G. LOCKHART Mem. Life W. Scott IV. v. 161 The surprised poet swung forth to join them, with an extemporized sandwich, that looked like a ploughman's luncheon, in his hand.] 1970 R. TREHANE in B. H. Axler Cheese Handbk. p. iii, English cheese and beer have for centuries formed a perfect combination enjoyed as the Ploughman's Lunch. 1971 Oxford Mail 27 Oct. 1/8 The loaf is to be cut into 200 pieces and eaten as part of 200 ploughman's lunches. 1973 P. THEROUX Saint Jack v. 60 We had a ploughman's lunch in the village—beautiful old pub—and went back to London. 1975 Times 30 Aug. 10/2 The pubs specialize in lunchtime catering..and you can get a decent ‘ploughman's’ for between 20p and 30p. 1977 J. THOMSON Case Closed v. 73 He treated himself to a ploughman's lunch of bread, cheese and pickle..at the Red Lion.