Green’s Dictionary of Slang

1. the head (cf. upper storey under upper adj.).

[1625		Bacon Apothgm No. 17: My Lord St. Albans said that wise Nature did never put her precious jewels into a garret four stories high, and therefore that exceeding tall men had ever very empty heads].
1690		‘Teague’ Teagueland Jests I 4: Our Dear Joy answered his Complement [...] not minding the Canary-Bird in the Garret.
c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Garret, or Upper Story. The Head. His Garret, or Upper Story, is empty, or unfurnished; i.e. he has no Brains, he is a fool.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn).
1811		Lex. Balatronicum [as cit. 1788].
1826		Lafitte 10: You know when John Bull gets plenty of corn in his garret, he is apt to be a little proud and dictatorial.
1837		R. Barham ‘The Bagman’s Dog’ in Ingoldsby Legends (1840) 335: While what’s called ‘The Claret’ / Flew over the garret.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1861		M.E. Braddon Trail of the Serpent 60: ‘Will you have the kindness to explain what you mean by the prisoner having “a loose slate?”’ ‘A tile off. Something wrong about the roof – the garret – the upper story – the nut.’.
1892		H. Lawson ‘The Captain of the Push’ in Roderick (1967–9) I 187: Would you break a swell or Chinkie—split his garret with a stone?
1903		‘Hugh McHugh’ Out for the Coin 79: Isn’t it wonderful how he can make people believe that there isn’t any furniture broken in his garret.
1904		Sun. Times (Perth) 3 July 4/7: His hat a billy lid, and on his frayed-out boots pieces of tin to keep the ants from getting to his garret.
1914		C. Holme Lonely Plough (1931) 190: As mun sewerly be a bit wrang in t’ garrets!
1926		Wood & Goddard Dict. Amer. Sl.
1939		Howsley Argot: Dict. of Und. Sl.

2. (UK Und.) the fob pocket.

1812		Vaux Vocab. of the Flash Lang.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1833		H. Smith Gale Middleton 1 149: The seedy had never a thimble in his garret, and never a sneezer in his sack.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1864, 1867, 1870		Hotten Sl. Dict.
1935		A.J. Pollock Und. Speaks.

3. the mouth.

1909

J. Ware Passing Eng. of the Victorian Era 39/2: Garret (Street, 19 cent.). Mouth — probably suggested by the mouth being high up in relation to all the body.

4. a woman’s handbag.

1984

Partridge DSUE (8th edn) 447/1: late C.19–20.