Green’s Dictionary of Slang

1. credit; esp. as on sock, on credit.

c.1698		B.E. Dict. Canting Crew.
1873		Sl. Dict.

2. a farthing.

1688

T. Shadwell Squire of Alsatia I i: I went up to the Gaming Ordinary and lost all my Ready; they left me not a rag or sock.

3. a pocket.

c.1698		B.E. Dict. Canting Crew n.p.: Sock c. a Pocket [...] Not a Rag in my Sock, c. I han’t a Farthing in my Pocket.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
c.1750–1882		B.M. Carew Life and Adventures.

4. the store of money itself, as hidden away in a bag, safe etc; a sum of money.

1904		Sydney Sportsman (Surry Hills, NSW) 5 Oct. 1/2: The article referred to simply dealt with the possible amount of real and personal estate that would be left by Adams, and surely there is no great harm in discussing the size of any person's sock’.
1931		Irwin Amer. Tramp and Und. Sl. 176: Sock.–The pocket or bank-roll.
1935		D. Lamson We Who Are About to Die 193: They got about nine grand in the sock up in their walk-up.
1949		W.R. Burnett Asphalt Jungle in Four Novels (1984) 137: Quigley lost a big sock horse-gambling.
1951		Cusack & James Come in Spinner (1960) 61: That’s what marriage without a sock in the bank would mean.
1953		D. Cusack Caddie 263: I had a tidy little sock in the bank.

5. anything used a receptacle for money, e.g. a wallet, a purse.

1911		E. Dyson ‘On a Bender’ in Benno and Some of the Push 79: The lady ’elp asked [...] if the legal infant ’ad the price iv the drinks he’d ordered in his sock.
1924		G. Henderson Keys to Crookdom 414: Pocketbook. Purse, poke, leather, sock.
1933		Ersine Und. and Prison Sl. 69: sock, n. Any place where one keeps money.
1943		‘“Ace” and its Progeny’ in AS XVIII:1 Feb. 71/2: ace-in-the-sock. An emergency or reserve fund or supply of money.

6. a filthy, messy room, i.e. as used by a student, young man etc. [coined by UK novelist Martin Amis (b.1949) and enjoyed brief popularity].

2001

Observer Rev. 24 June 3: You’ve got to have somewhere you can go and hide, your own ’sock’ as Martin Amis said.

7. (N.Z. prison) constr. with the, a weapon created by tying something heavy, e.g. a pool ball, into a sock [? underpinned by sock n.² (1)].

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 172/2: sock, the n. a weapon made from a pool ball in a sock.