Green’s Dictionary of Slang

1. (Anglo-Irish) a public house sweetheart [? she is ‘hot stuff’].

1821

‘A Real Paddy’ Real Life in Ireland 126: Every carman rode on double horses, behind them sat their dames and gridirons (public-house sweethearts).

2. a harp.

1846

Swell’s Night Guide 34: As a sort of whipper-in, music is provided – viz., a gridiron, a joano, and a squeaker, as they are fancifully named, a harp, piano, and flageolet.

3. in London, a county court summons [the arms of the City of Westminster, which resemble a gridiron].

1859		G.A. Sala Gaslight and Daylight 240: He collects debts for anybody in the neighbourhood, takes out the abhorred ‘gridirons,’ or County Court summonses [etc.].
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict. 183: Gridiron a County Court summons. Originally a summons to the Court of Westminster only; from the gridiron arms.
1895		Crowe Aus. Sl. Dict. 33: Gridiron, a County Court summons.

4. (US) the US flag, the ‘stars and stripes’.

1876

Sporting Gaz. (London) 10 June 15/1: For the benefit of the uninitiated, Mr. Davenport kindly explains his title in his preface; ‘in nautical slang “The Gridiron” is only another for the American Ensign’.

5. the bars on a prison-cell window.

1890–1904

Farmer & Henley Sl. and Its Analogues.

6. (US) a football field [post-WWII use is SE].

1895		J.S. Wood Yale Yarns 95: She had asked him if he imagined he was carrying a foot-ball through a Princeton rush line [...] His prancing step, she intimated, was perhaps better adapted to the ‘gridiron’ than the drawing-room floor.
1897		N.Y. Journal 5 Sept. 41/4: Captain Garret Cochran will marshal a small army of gridiron warriors on the ‘varsity athletic ground’ [DA].
1909		Eve. Star (Wash., DC) 17 Oct. 5/3: [heading] making a gridiron hero.
1913		Collier’s 20 Dec. 27/2: He is one of the best handlers of the ball on the gridiron [DA].
1915		R. Bolwell ‘College Sl. Words And Phrases’ in DN IV:iii 236: grid. Gridiron: meaning 1. football field; 2. a gridiron player.
1923		H.C. Witwer Fighting Blood 268: One day we gaily set forth for the courts, or links, or gridiron, or whatever.
1926		A. Angel ‘Golf Gab’ in AS I:12 627: Football has developed [...] ‘gridiron,’ or ‘moleskin’.
1929		H.C. Witwer Yes Man’s Land 101: ‘Great sport, this!’ he says, with an airy wave at the gridiron.

7. a bicycle.

1953

A. Buckeridge Jennings’ Diary 71: But I can’t pedal like blinko on that old gridiron.