Pet peeve of mine but technically prison is for convicts, jail is for those yet awaiting a conviction but who aren't trusted to show up to court if allowed to roam freely. That the jail system (in the US especially) has essentially become a form of preemptive incarceration without the presumption of innocence is largely an artefact of the bond system, the overwhelmed courts and the perverse incentives in all of those systems from law enforcement to private prisons.
I realize the terms are often used interchangeably but I think the distinction is important especially because of the implications for presumption of innocence from conflating the two.
> Pet peeve of mine but technically prison is for convicts, jail is for those yet awaiting a conviction but who aren't trusted to show up to court if allowed to roam freely.
Pet peeve, but despite being a frequently claimed technical distinction, this is wrong both in terms of the strict definition of the terms and the way they are used as names of real institutions (though it is approximately true in most US state justice systems—but not the federal system—if you consider only felony crimes.)
> Merriam-Webster has it as "chiefly British spelling" of jail
It's odd that it doesn't mention it as archaic, because it's provably Just Not Used in the real world [0], but it's also an American dictionary, so all bets are off
If you click on the entry your search results give, it takes you to the entry for jail (eg: jail is the canonical noun it's using). Jail and gaol have slightly different routes into English, with gaol being via Northern French. Sez the OED:
> "remains as a written form in the archaic spelling gaol (chiefly due to statutory and official tradition); but this is obsolete in the spoken language, where the surviving word is jail, repr. Old Parisian French and Middle English jaiole, jaile. Hence though both forms gaol, jail, are still written, only the latter is spoken. In U.S. jail is the official spelling."
Finally, though, "jail" as a noun is pretty infrequent compared to "prison", which are the same thing in the UK (unlike the US), but the latter is much more common. The verb form on the other hand is almost always "jail", so when you are "jailed", you're sent to a prison.
> I believe Collins is the standard dictionary that British people use
And you would be wrong. They've only been putting out a dictionary since 1979. OED[0] is The Dictionary in the UK, and I've quoted its take on it in an adjacent comment.
Well, come on, that's obviously false. Zero percent of British people own an OED or even have the resources necessary to consult one when they want to look something up. It costs over a thousand US dollars.