It just occured to me how the nickname “pokey” was created to mean jail.
It’s an old term, originally spelled “poky” meaning a place which is “petty in size or accomodation, affording scanty room to stir; confined, mean, shabby” according to the OED. Not a big stretch to apply that to a jail cell. It’s related to “poke” as in a sack (“pig in a poke”), again not a big stretch to apply that to being bagged by the peelers.
It’s still used quite commonly in British English as a disparaging description of a small room, house, etc.
Jail: slang terms for;
Pokey
Hoosgow (Houss - gaow)
Slammer
Lock-up
Big house
Hole
Clink
Jug
Lag
Observation: Not nice places.
Suggestion: Avoid them.
Originally the term pokey did not refer to the jail itself, but instead described a new prisoner who dropped the soap in the shower and didn’t know enough to leave it there.
and “up the river”, which refers to Sing Sing[sup]1[/sup] being up the Hudson from New York. Clink, by the way, also refers to a specific prison, one in the London area. It’s now a museum.
[sup]1[/sup] Yes, I know it’s now called Ossining. Sing Sing sounds better.
Chokey
Free Parking
Gumby’s pal got dragged in so often for public intoxication that the place was named for him.
I’ll just throw in that JBENZ’s etymology seems reasonable to me, but that Merriam-Webster’s Collegiate® Dictionary says “origin unknown” and dates the word to 1919.
Please, let us not forget;
“The Graybar Hotel”
Or to quote Tom Clancy (maybe);
“Substandard Federal housing with substandard companions.”
I came here looking for why they called the room with the cage on NYPD Blue ‘the pokey’ and saw clink for a jail slang - which is how the Hogan’s Heroes writers came up with Colonel Klink for the head of a prison camp. ‘Schultz’ BTW in old German is a village leader responsible for protection, not that far from a guard - the Hogan’s writers did some research into naming the characters at least. 
yup - the guy behind him was the poker, he was the pokee.
The timing on this resurrected thread is funny. I was just thinking of asking how the term “in stir” came about. Heard it in an old movie a few days ago.
Not sure if I’m being whooshed here but I think the character in Hogan’s Heroes was named after the similar character in Stalag 17.
I never saw Stalag 17, but I guess HH’s writers could’ve copied from the movie.
From etymonline.com under stir-crazy.
“psychologically deranged as a result of confinement or imprisonment,” 1908, thieves’ slang, from crazy (adj.) + stir (n.) in a slang sense of “prison, lock-up” (by 1851), which is of uncertain origin but said to be from Start Newgate (1757), the prison in London, later any prison (1823), and that probably from Romany stardo “imprisoned,” which is said to be related to staripen “a prison.” According to Barnhart, mid-19c. sturaban, sturbin “state prison” seem to be transitional forms.
But a big but. The word isn’t recorded in that usage until as late as 1851. “The Oxford English Dictionary first cites stir in Henry Mayhew’s 1851 journalistic investigation, London Labour and the London Poor. His interviewees mention folks “in stir” or “out of stir,” or, as Mayhew helpfully glosses, jail or prison.”
So origin unknown as of this point.
At the risk of derailing this old thread even further. THe playwriters of Stalag 17 sued the producer of Hogan’s Heroes because of how close the themes were. Even the pilot tracked the plot of the movie a bit, and the somewhat inept guard’s name in both was ‘Schultz.’ Stalag 17 was largely NOT a comedy, but there were some comedic bits in it.
The lawsuit was lost though and even though it’s clear that Hogan’s Heroes was at least inspired by Stalag 17 it was ultimately deemed to not infringe.
Dalia Dippolito was arrested for plotting to murder her husband. When Dalia called her mother from jail, Dalia told her mother she was at Gun Club, and mom knew what that was. That may be an idiom only in Florida. I’d never heard it before.
YouTube/google her name for an interesting story.
Simple me: I figured it referred to getting poked into the cell.
ETA, someone brought up pig in a poke or poke sack . I often refer my purse or bag as my Poke or my Necessary
Isn’t Hoosgow just a corruption of the Spanish Juzgado ( a Court of Adjudication)?