A preposition, a specific type of adposition, is a word describing a relationship between two nouns. These include words such as "on", "to", "beneath", "before", etc.
As noted in the link, the word is a lot more complex than it seems, and not every use of a word that looks like a preposition is one. But the most well-known thing about them is that you supposedly cannot end sentences with them (also known as stranding a preposition).
One oft-claimed source of this is some overzealous grammarians' attempts to apply Latin grammar rules to English, and while some of those can actually apply in the latter language (like no double negatives), this one doesn't (same with splitting infinitives, which is impossible in Latin). Many sentences just don't flow in English if this rule is shoehorned in, and evidence has been shown that ending sentences with prepositions has been in the language since Anglo-Saxon. Some grammarians analyzed other languages, even quite unrelated languages such as Irish or Scottish Gaelic, with models based upon Latin grammar, to various degrees of success and correctness.
A more concrete source of this grammar superstition is an English grammarian named Robert Lowth, who wrote the highly-influential A Short Introduction to English Grammar in 1762. He actually discussed, in his grammar, separating prepositions from the relative that they govern. He said that it was an idiom "which our language is strongly inclined to" and fit the "familiar style" but did not fit the "solemn and elevated style". In other words, his critique of this was based upon style, not grammar. Unfortunately, some teachers and grammarians probably misinterpreted this as an absolute rule, whence came the superstition. Lowth himself warned against overapplication of Latin rules to English.
In fiction, there are different reactions to this. The person who states the rule might be accused of being a Grammar Nazi. Or those called on for doing this might reply in a snarky manner, a common spin being repeating the sentence but concluding with an insult ("Where do you come from, bitch?"). Or those called on might instead try their best to avoid breaking this rule. Basically it's whichever is funnier.
If someone tries to call you on this, tell them that the Oxford University English Department says it's perfectly acceptable, and that you recognize no higher authority. And then say something that ends in "off".
Can often invoke In Which a Trope Is Described, the title of which is the pedant's version of 'a trope is described in'.
- Y: The Last Man: Yorick, as an English major, is somewhat pedantic about language usage. Even during his final declaration of love.
Yorick: I knew I wanted to keep living in any world that you were a part of. But that was hard to admit to myself, and not just because it ended with a preposition.
- Gold Key's adaptation of The Inspector cartoon "Le Quiet Squad" has Sgt. Deux-Deux barging in on the Inspector:
Deux-Deux: Inspector! I have spotted something you may be interested in!
Inspector: Sergeant! How many times must I tell you... never end a sentence with a preposition! You should have said "in which you may be interested!"
- An early Dilbert strip had a woman saying, "Up I hic!" In the last panel, Dogbert clarified that she's an English teacher.
- In one Mother Goose and Grimm strip, a delivery man asks Ham the pig "Where should I put these groceries at?" After Ham corrects the guy's grammar, the grocer corrects himself with "Where should I put these groceries at, slimeball?"
- In Beavis and Butt-Head Do America, Agent Flemming admonishes a fellow ATF agent for doing this. That agent then ties his sentences in knots trying to get around this. Having learned the lesson, the latter later stumbles again and attempts to paraphrase, only to be reprimanded for getting preoccupied with unimportant things when it's an emergency.
- In Canadian Bacon, one of the Mounties tells the heroes to "go back to where you came from." The other Mountie tells him that you can't end your sentence with a preposition, and proceed to debate this while the heroes escape.
Mountie #1: Oh really. Well, what would you say?
Mountie #2: Well, I guess I'd say either, "Go back from where you came", or the preferred Queen's English, "Go back, thee, from whence thou came."
- With Honors: A homeless man attending a class at Harvard (long story) gets in an argument with the Professor. So when he wants to leave, this exchange happens:
- Simon Wilder: Which door do I leave from?
Professor Pitkannan: At Harvard we don't end our sentences with prepositions.
Simon Wilder: Okay. Which door do I leave from, asshole?
- Scary Movie 4 does this with Brenda in its parody of The Village.
Brenda: This is shit up with which we shall not put!
- The Wolf Of Snow Hollow: One of the murder victims has an angry voicemail on her work phone from a man. He conspicuously words his final sentence in a non-conversational manner so that it doesn't end in a preposition. In the process, he also uses the word "whom," which John comments on.
- The story of a working class freshman on his first day at (insert prestigious university of choice) who asks "Can you please tell me where the bathroom is at?" and is publicly humiliated for being so crass as to end a sentence with a preposition, and told to rephrase his question without breaking this rule. To which he replies "OK. Can you please tell me where the bathroom is at, asshole?"
- A similar exchange on some greeting card:
- Woman 1: Where's your birthday party at?
Woman 2: Don't end a sentence with a preposition.
Woman 1: Where's your birthday party at, bitch?
- In Designing Women Charlene tells this old anecdote:
"I asked this Northern woman, 'Where are y'all from?' And she said, 'I'm from a place where we don't end our sentences with prepositions.' So I said, 'Okay, where are y'all from, bitch?'"
- There's an episode where Martin is writing someone a letter and Niles, reading over his shoulder, corrects him for ending a sentence with a preposition. We see Martin, rather annoyed, writing something on the paper and underlining it, gesturing to Niles, to which Niles replies, "Not to be technical, but 'off' is a preposition too."
- In another episode Frasier corrects a caller who uses the word "literally" in the completely wrong way, bringing said caller to get angry about people who "nitpick on your grammar when they come to you for help".
Doug: That's what I got a problem with! [Hangs up]
Frasier: ...I think what he means is, that is a thing with which he has a problem.
- In Cheers episode "Diane's Nightmare", Diane dreams that Sam's boorishness has just been an act for the bar patrons; he's actually cultured and erudite. As he plays her a classical piano piece of his own composition, she embraces him and says, "Forget the piano. Let me be the instrument you play on." Sam's response: "Diane, do you realize you just ended that proposition... with a preposition?" This is a Running Gag between those two, first used in "The Tortelli Tort". When Ed threatens to sue the bar over Carla assaulting him, Sam tries to convince him that Carla is getting therapy for her anger problems:
Sam: She's trying to become the kind of waitress that you'd enjoy being waited on by.
Diane: You just ended that sentence with two prepositions...
Sam: Don't you have customers to deal with?
Diane: That ended with a preposition, too...
Sam: Don't you have customers to deal with, mullet head?
- One Stargate SG-1 episode has one of the villains wondering why O'Neill isn't doing the quips he's become famous for. Later on, O'Neill obliges.
Her'ak: No matter what you have endured, you have never experienced the likes of what Anubis is capable of.
O'Neill: You ended that sentence with a preposition. Bastard.
- In 30 Rock Tracy Jordan tells an intern "You shouldn't end a sentence with a proposition at".
- In one episode of The Drew Carey Show, Mr. Wick threatens to fire the next employee who ends a sentence with a preposition, immediately following the threat by saying, "Now, where has Mimi gotten to? (Beat) ...He inquired!"
- In The Big Bang Theory episode "The Jerusalem Duality", fifteen-year-old North Korean physics genius Dennis Kim, who has only been speaking English for a year and a half, pulls this one out. Leonard tells Dennis that he speaks English well, only to receive the condescending response that Leonard does as well, except for the fact that he regularly ends his sentences with prepositions. Then Leonard asks, "What are you talking about?", and Dennis quickly lampshades this (thence to become Sheldon's new Sitcom Archnemesis).
- In one of the Red Dwarf script books, Grant Naylor say that they're often asked "Where do you get your ideas from?" and that this question always annoys them because it ends with a preposition "and as we all know, that's not something you should end a sentence with. Damn."
- An episode of Everybody Loves Raymond deals with Ray Barone being asked to make informed comment on the amount and quality of homework assigned to kids at his daughter's school. Being Ray, he neglects this task and his mother has to bail him out. She chews him up for ending sentences with a preposition. He also does this when reporting back to the school's governors. One turns to the English teacher and says.
"And you really want to cut the amount of homework we give them?"
- In Two and a Half Men combined with Flipping the Bird:
Alan: Jake, why did you flip Miss Pasternak off?
Pasternak: Excuse me. We don't end our sentences with prepositions. We say, "Why did you flip off Miss Pasternak?"
Charlie: I think that answers your question.
- From Comedy Central's The Blue Collar Comedy Tour, when Bill Engvall is telling "Here's your sign" anecdotes:
Larry the Cable Guy: Hey, tell 'em about the one you done did over at the whatcha-call-her.
Jeff Foxworthy: [pause] Yeah, Bill. Tell 'em about the one you done did over at the whatcha-call-her.
Ron White: He just ended a sentence in nine prepositions.
Bill: He's an over-achiever.
Larry: I don't know about all that, but... (Bill cracks up laughing)
- In The Last Man on Earth, Carol the pedantic Grammar Nazi annoys Phil to no end by insisting on correcting him every time he ends a sentence with a preposition.
- A Not the Nine O'Clock News sketch has this as its punchline. A student is scolded by the headmaster for failure to improve in his schoolwork. It turns out he's been using slightly-modified versions of his admission essay ("My aunt, who I live with, used to have a parrot...") whenever he has to write a paper. After going over some examples, the headmaster yells:
"Do you think I'm some sort of idiot? Did you think I wouldn't notice? It's with whom I live!"note
- Eugene Meltsner of Adventures in Odyssey adheres to this. In one episode, consistently losing chess games to the local janitor has begun taking a toll on his sanity, and his friends are alarmed when he ends a sentence with a preposition. His reaction?
Eugene: Sometimes I'm convinced that this is a game he doesn't even know the rules for!
Connie: Eugene, you just ended a sentence with a preposition!
Eugene: That's impossible! Prepositions are not words I end sentences with!
- This is a running gag in Kingdom of Loathing, even including sentences where the word isn't being used as a preposition.
- In one of the The Order of the Stick comics that appeared in Dragon magazine, Vaarsuvius rages at a pair of undead who end every single sentence with a preposition. When Durkon reproaches him for acting like an uptight English teacher, Vaarsuvius replies, "What is this 'English' of which you speak?"
- Shows up in this The Perry Bible Fellowship strip.
- This is what sparks the hilarity in the Hitler Rants video "Downfall of Grammar".
- Played for laughs in CollegeHumor's parody of Inglourious Basterds:
Perrier LaPadite: I swear I do not know where Mademoiselle Dreyfus was at!
Col. Hans Landa: Did you just end a sentence with a preposition?
Perrier LaPadite: ...Forgive me, Colonel.
- Phineas and Ferb: In the first episode, "Rollercoaster", Phineas complains about not having anything interesting to do during summer vacation, saying "Boredom is something up with which I will not put!"