Green’s Dictionary of Slang

1. the prize ring, a generic term for the world of prize-fighting and pugilism.

1827		Egan Anecdotes of the Turf, the Chase etc. 25: [note] I believe he never fought in the P.R.
1832		Egan Bk of Sports 24: Such was the interest manifested by the Fancy to see the pet once more in the P.R.
1842		Whip & Satirist of NY & Brooklyn (NY) 29 Jan. n.p.: Maude was unknown to the P.R.
1845		Bell’s Life in Sydney 18 Oct. 2/4: It was a wish he had always cherished since he had taklen a standing in the P.R.
1849		Sam Sly 31 Mar. 1/1: Jem [Burn] has always been an honest member of the P.R.
1853		N.Y. Clipper 13 Aug. 1/5: His experience in the P. R., combined with his superiority in weight and strength, would compensate.
1854		‘Cuthbert Bede’ Adventures of Mr Verdant Green (1982) II 172: The Pet, who had been [...] wondering whether the gentleman named Dares, who caused the death of beauties, was a member of the P.R.
1857		Bell’s Life in Victoria (Melbourne) 23 May 3/6: [P]rior to the present mill [he] has fought some four or five times in the P.R.
1866		Night Side of N.Y. 42: Finally he will back down, on the objection that pistols are not in accordance with the rules of the ‘London P.R.’.
1869		J. Greenwood Seven Curses of London 379: Some brief account of a ‘mill’ that has recently taken place between those once highly-popular gentlemen — the members of the ‘P.R.’.
1873		J. O’Connor Wanderings of a Vagabond 316: When the news of the bombardment of Fort Sumter reached New York, the rowdy element [...] formed themselves into several regiments, some of which were officered with shining lights of the P.R.
1878		‘’Arry on the Turf’ in Punch 29 Nov. 297/1: And now the P.R. is a frost, / If it weren’t for the race-course, by Jove, British grit would be jest about lost.
1885		Bulletin (Sydney) 21 Feb. 14/2: Another big fight had, it is said, been arranged to take place in London soon after Christmas. The P.R. is decidedly ‘looking up.’.
1886		Sporting Times 13 Feb. 5/5: A great patron of the P.R., and can put up his ‘dooks’ to some purpose.
1894		Truth (Sydney) 18 Mar. 2/6: Ladies [...] were disputing the possession of some greasy, hairy Adonis after the most approved principles of the P.R.
1902		Bulletin (Sydney) 4 Oct. 26/3: Neither, however, may hold with one arm and thump with the other, as this practice gives a strong man a big pull over a weaker [...] adversary, in that when at close quarters the more powerful fighter might hold his adversary and punch away for seconds at a stretch – the ‘head in chancery’ of the P.R.
1909		J. Ware Passing Eng. of the Victorian Era.

2. (drugs) marijuana [abbr. Panama Red].

1969		R.R. Lingeman Drugs from A to Z (1970) 201: Panama red, also called P.R., red. Local variety of marijuana, grown in Panama.
1971		E.E. Landy Underground Dict. (1972).
2001		ONDCP Street Terms 16: P.R. — Panama Red.