# chain

Pronunciation: say "CHAYN" /ˈt͡ʃeɪn/

## Noun

1. A series of connected rings or links, usually made of metal, used for pulling, fastening, or securing things.
   - Simple: A line of rings joined together, usually metal, used to pull, hold, or lock things.
   - _The anchor hung from a heavy iron chain._
   - _He locked his bike to the fence with a heavy chain._
2. A series of things connected to one another, with each one linked to the next.
   - Simple: A group of things that are joined or connected one after another.
   - _A chain of small mistakes led to the accident._
   - _The volcanic islands form a chain stretching across the Pacific._
3. A series of stores or businesses operating under the same brand name.
   - Simple: A group of stores or restaurants that all have the same name and are run in the same way.
   - _The coffee chain opened its hundredth location this year._
   - _National chains have replaced many of the local shops downtown._
4. A strand of small interlocking metal links worn as jewelry on the neck or wrist, often with a pendant hanging from it.
   - Simple: A piece of jewelry made of small metal rings joined together, worn around the neck or wrist.
   - _She fastened a delicate gold chain around her neck, and the locket settled just below her collarbone._
   - _The jeweler laid out a row of fine chains, each long enough to carry a pendant._
6. A series of atoms bonded one after another, forming all or part of a molecule.
   - Simple: A line of atoms joined one after another inside a molecule.
   - _Octane contains a chain of eight carbon atoms._
   - _Polymers form when small molecules join into long chains._
7. Something that confines, holds, or secures a person or thing; a bond.
   - Simple: Something that holds a person back and keeps them from being free.
   - _He came to see his debts as a chain holding him in place._
   - _The speech urged listeners to throw off the chains of ignorance._
11. A sequence of linked house purchases, each depending on the one before and after it; the sequence is said to be broken if a buyer or seller pulls out. *(British)*
   - Simple: In Britain, a line of house sales where each one depends on all the others.
   - _Their flat sale collapsed when the chain broke two weeks before completion._
   - _Being first-time buyers with no chain made their offer more attractive to the sellers._
12. An ornamental collar of linked metal worn as a sign of office or rank; a livery collar.
   - Simple: A special necklace of metal links that a mayor or other leader wears to show their job.
   - _The mayor wore her chain of office at the ribbon-cutting ceremony._
   - _The portrait shows the alderman in a fur robe and a heavy gold chain._
13. A surveyor's measuring device of known length, made of connected links or a long tape, used to measure distances on the ground.
   - Simple: A long line of links or tape that surveyors use to measure land.
   - _The surveyor stretched the chain between the two boundary markers._
   - _Early county maps were drawn from measurements taken with chains and compasses._
14. A unit of length equal to 22 yards (4 rods or 100 links), approximately 20.12 meters; also the length of a cricket pitch.
   - Simple: A unit for measuring length equal to 22 yards, or about 20 meters.
   - _The deed describes a parcel eight chains wide along the county road._
   - _From wicket to wicket, a cricket pitch measures exactly one chain._
16. In mathematics, a totally ordered set, especially a totally ordered subset of a partially ordered set.
   - Simple: In math, a set where any two members can be compared, so one always comes before the other.
   - _Every nonempty chain in a finite poset has a greatest element._
   - _The subsets {1}, {1,2}, and {1,2,3} form a chain under inclusion._

## Verb

5. To fasten, secure, or restrain someone or something with a chain or chains.
   - Simple: To tie up or lock someone or something with a chain.
   - _Workers chain the heavy equipment to the truck bed before long drives._
   - _She chained her bicycle to a lamppost outside the library._
8. To bind or tie someone to something, such as a job, duty, or habit, as if holding them with a chain.
   - Simple: To keep someone stuck to a job, duty, or habit, as if with a chain.
   - _Years of debt chained him to a job he hated._
   - _Nostalgia can chain people to a past that no longer exists._
9. To link multiple items together, or to become linked together, into a connected series.
   - Simple: To join together one after another in a connected line.
   - _The plastic barriers chain together to close off the street._
   - _If you chain the short exercises together, they make a full twenty-minute workout._
10. In computing, to link data items together, or to be linked, so that each item points to the next.
   - Simple: In computing, to join pieces of data so each one points to the next.
   - _The file system chains free blocks into a single list the allocator can walk._
   - _Hash tables often chain colliding entries rather than searching for an open slot._
15. To measure distances on land using a surveyor's chain or measuring tape.
   - Simple: To measure distances on land with a surveyor's chain or a long measuring tape.
   - _Early surveyors chained the boundary line across miles of rough prairie._
   - _Crews would chain each section line before setting the corner monuments._
17. To obstruct a river mouth, harbor entrance, or other waterway by stretching a chain across it.
   - Simple: To block a river or harbor by stretching a heavy chain across it.
   - _The garrison chained the river below the fortress to stop the gunboats._
   - _Medieval ports would chain the entrance channel at dusk and open it again at dawn._

## Verb

18. To load a program into memory and run it automatically, typically replacing the program currently executing. *(rare)*
   - Simple: To make a computer load a program and start it right away.
   - _In old versions of BASIC, one program could chain another, which then replaced it in memory._
   - _Old BASIC programs would chain a second program when they grew too large for memory._

## Other meanings

- (noun) In homological algebra, an element of one of the groups or modules making up a chain complex.
- (noun) In topology, a formal sum of cells of a given dimension in a CW complex, or of simplices or cubes of a given dimension in a simplicial or cubical complex.
- (noun) Iron links bolted to the side of a ship to hold the dead-eyes that secure the shrouds; also, the channels themselves.
- (noun) The warp threads of a woven fabric; the lengthwise threads through which the weft is passed.

## Origin

Chain came into Middle English as cheyne or chaine, borrowed from Old French chaine, which came from Latin catēna ("chain"), whose earlier origin is uncertain. It is a doublet of catena.

Source: DictionaryAI, https://dictionaryai.com/define/chain (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).