in

Etymology 1

PIE word *h₁en Preposition and verb from Middle English in, from Old English in, from Proto-Germanic *in. Adverb, noun and adjective from Middle English in, from Old English inn and inne, from Proto-Germanic *innai. Sense 1/2 "in"/"into" are from the original PIE prefix, with locative/accusative case respectively. Sense 3/4 "qualification"/"means" are from the PIE metaphor of all infinitives coming from locatives.

prep

1. Used to indicate location, inclusion, or position within spatial, temporal or other limits.
   1. Contained by.
      The dog is in the kennel.
      There were three pickles in a jar.
   2. Within the bounds or limits of.
      I like living in the city.
      There are lots of trees in the park.
      GDP measures the total value of output in an economic territory. 2013-08-03, “Boundary problems”, in The Economist, volume 408, number 8847
   3. Surrounded by; among; amidst.
      We are in the enemy camp.
      Her plane is in the air.
      Waiter! There's a fly in my soup!
   4. Wearing (an item of clothing).
      I glanced over at the pretty girl in the red dress.
   5. Part of; a member of; out of; from among.
      You are one in a million.
      She's in an orchestra.
   6. During (a period of time).
      My birthday is in the first week of December.
      Easter falls in the fourth lunar month.
      The country reached a high level of prosperity in his first term.
   7. Within (a certain elapsed time); by the end of.
      Will you be able to finish this in a week?
      The massacre resulted in over 1000 deaths in three hours.
   8. At the end of (a period of time).
      They said they would call us in a week.
   9. (grammar, phonetics) Characterized by.
      Many English nouns in -is form their plurals in -es.
2. Into.
   The ball was accidentally kicked in Kevin Nolan's face in the opening seconds of the contest – an incident that set the tone for an extremely uncomfortable encounter for the Premier League side. January 8, 2011, Paul Fletcher, “Stevenage 3-1 Newcastle”, in BBC
   Less water gets in your boots this way.
   She stood there looking in the window longingly.
3. Used to indicate limit, qualification, condition, or circumstance.
   1. Indicating an order or arrangement.
      My fat rolls around in folds.
   2. Denoting a state of the subject.
      He stalked away in anger.
      John is in a coma.
   3. Indicates, connotatively, a place-like form of someone's (or something's) personality, as his, her or its psychic and physical characteristics.
      You've got a friend in me.
      He's met his match in her.
   4. Pertaining to; with regard to.
      There has been no change in his condition.
      What grade did he get in English?
4. Used to indicate means, medium, format, genre, or instrumentality.
   1. (of something offered or given in an exchange) In the form of, in the denomination of.
      Please pay me in cash — preferably in tens and twenties.
      The deposit can be in any legal tender, even in gold.
      Her generosity was rewarded in the success of its recipients.
      […] tourists sometimes attempt to pay in euros or British pounds. 2014, Carla Bethmann, Clean, Friendly, Profitable?: Tourism, page 114
   2. Used to indicate a language, script, tone, etc. of a text, speech, etc.
      Beethoven's "Symphony No. 5" in C minor is among his most popular.
      His speech was in French, but was simultaneously translated into eight languages.
      When you write in cursive, it's illegible.
      Military letters should be formal in tone, but not stilted.

verb

1. (obsolete, transitive) To enclose.
2. (obsolete, transitive) To take in; to harvest.

adv

1. At or towards the interior of a defined space, such as a building or room.
   Suddenly a strange man walked in.
   Would you like that to take away or eat in?
   He ran to the edge of the swimming pool and dived in.
2. Towards the speaker or other reference point.
   They flew in from London last night.
   For six hours the tide flows in, then for another six hours it flows out.
3. So as to be enclosed or surrounded by something.
   Bring the water to the boil and drop the vegetables in.
4. After the beginning of something.
   The Black Cats had a mountain to climb after James Morrison's header and Shane Long's neat side-foot finish gave Albion a 2-0 lead five minutes in. October 1, 2011, Phil Dawkes, “Sunderland 2-2 West Brom”, in BBC Sport
   The show still didn't become interesting 20 minutes in.
5. (in combination, after a verb) Denotes a gathering of people assembled for the stated activity, sometimes, though not always, suggesting a protest.
   sing-in, pray-in, hug-in; see also be-in, love-in, sit-in, teach-in.

noun

1. A position of power or influence, or a way to get it.
   His parents got him an in with the company.
2. (chiefly in the plural) One who, or that which, is in; especially, one who is in office.
   This memoir has nothing to do with the question between the ins and the outs; it is intended neither to support nor to assail the administration; it is general in its views upon a general and national subject; […] 1827, Benjamin Chew, A Sketch of the Politics, Relations, and Statistics, of the Western World, page 192
3. (sports) The state of a batter/batsman who is currently batting; see innings.
4. A re-entrant angle; a nook or corner.

adj

1. (not comparable) Located indoors, especially at home or at one's office or place of work.
   Is Mr. Smith in?
2. (not comparable) Located inside something.
   Little by little I pushed the snake into the basket, until finally all of it was in.
3. (sports, of the ball or other playing implement) Falling or remaining within the bounds of the playing area.
   If the tennis ball bounces on the line then it's in.
4. Inserted or fitted into something.
   I've discovered why the TV wasn't working – the plug wasn't in!
5. Having been collected or received.
   The replies to the questionnaires are now all in.
6. In fashion; popular.
   Skirts are in this year.
7. Incoming.
   the in train
8. (nautical, of the sails of a vessel) Furled or stowed.
9. Of the tide, at or near its highest level.
   You can't get round the headland when the tide's in.
10. (law) With privilege or possession; used to denote a holding, possession, or seisin
    in by descent; in by purchase; in of the seisin of her husband
11. (cricket) Currently batting.
12. Having familiarity or involvement with somebody.
    “[…] He […] took a rifle out of the batch and shot at me. I was lucky he was such a crummy shot.” “Why would he do that?” “I think he's in with them, Doctor.” “Them? You mean Ned and Cody?” “All of them. Hickok, the split tail, the whole lot.” 2010, Joe R. Lansdale, Flaming Zeppelins: The Adventures of Ned the Seal, page 123
    He is very in with the Joneses.
13. (informal) Having a favourable position, such as a position of influence or expected gain, in relation to another person.
    I think that bird fancies you. You're in there, mate!
    I saw this thing on ITV the other week, Said, that if she played with her hair, she's probably keen She's playing with her hair, well regularly, So I reckon I could well be in. 2004, The Streets (lyrics and music), “Could Well Be In”
14. (of fire or fuel) (Britain, Ireland, Australia, New Zealand) Burning; ablaze.
    Blocks of compressed coal keep the fire in for a long time, but they give out very little heat. 1888, H.C. O’Neill, Edith A. Barnett, Our Nurses and the Work They Have to Do, page 81
    “At all events,” said the Doctor, “the fire’s in, and here’s the camp-oven, too. Somebody will be here soon. I will go in and light my pipe.” 1894, Henry Kingsley, The Recollections of Geoffry Hamlyn - Volume 2, page 183
    Was there any person in your own house at Renmore to keep the fire in while you were here?. 1901, William Francis Barry, The Wizard’s Knot, page 231
    Normally when they camped in the wild they took turns to sit up and keep the fire in while the others slept, […]. 2011, Rosemary Sutcliff, The Eagle of the Ninth Chronicles
    He turned and started making up the range to keep the fire in overnight, and heard the front door click and Grant’s motor fire up. Sleep. He needed to sleep. 2019, A.L.Lester, Shadows on the Border
15. Having used, consumed , or invested a certain amount.
    I'm three drinks in right now.
    I was 500 dollars in when the stock crashed.

Etymology 2

noun

1. Abbreviation of inch; inches.