circuit
Pluralcircuits
Pluralcircuits
Formscircuits, circuiting, circuited
- 1A closed path along which an electric current flows, usually arranged to perform a particular function.
Like a closed road loop: traffic keeps moving only while the whole loop stays unbroken.
Engineers traced a fault in the circuit before replacing the burned-out resistor.
Each circuit on the board draws power from the same battery.
Note
An electrical circuit has to close: current leaves its source and returns to it, and a break anywhere stops the flow. Circuits are built up from smaller ones, so engineers speak of sub-circuits wired in series or in parallel. Within those sub-circuits, the parts can often be rearranged without changing what the whole circuit does.
- 2A track laid out for racing, usually forming a loop that competitors complete one or more times.
Like an athletics oval, but built for engines instead of legs.
The drivers completed forty laps of the circuit under heavy rain.
This circuit is famous for its tight hairpin turns.
Similartrack, course, racetrack
Note
Racing writers use circuit and track almost interchangeably. One 2016 Formula 1 report called Interlagos a track and Baku a circuit within two sentences. Circuit suggests a closed loop raced lap after lap. The season's list of venues is its calendar, so a circuit joins the calendar or sits on it.
- 3A regular round of visits from place to place, made as a fixed part of someone's job.
Like a paper route, but the stops are towns instead of houses.
The traveling nurse covers a rural circuit spanning six small towns.
A preacher on the circuit might lead services in three churches each Sunday.
Similarround, route, beat, tour
Note
Performers use this word as freely as traveling officials do. A comedian who has cut his teeth on London's comedy circuit learned the trade on that round of venues. A descriptive noun usually goes in front, and the preposition is on: you are on the circuit, or you work it.
- 4One complete pass through every exercise in a circuit-training routine before any exercise is repeated.
Like completing one verse-and-chorus before looping the song again.
After one circuit of squats, push-ups, and lunges, his legs were burning.
The trainer had us power through five circuits before cooldown.
Similarround
- 5The distance around the outside of a space; the length of the line enclosing an area.
Like the perimeter fence of a field: the total length of its boundary.
The ancient city walls had a circuit of nearly five miles.
Walkers can trace the full circuit of the island in a single day.
Similarcircumference, perimeter
- 6The act of moving around something in a circle or orbit; one full revolution.
Like the second hand sweeping once around a clock face.
Each circuit of the sun takes the planet nearly two years.
The satellite completes a circuit of the globe in ninety minutes.
Similarorbit, revolution, lap
Note
Latin gave the word its picture: circuitus, "a going round," from circuire, built from circum "around" and the verb for going. That picture is still literal here, in a moon or planet completing its trip back to the start. A circuit is counted as one whole return, which is why Popular Science Monthly in 1904 could say the moon must make "one circuit and a little more."
- 7The territory within which certain judges hold court, whether they travel between locations or sit in one place.
Like a region assigned to a single inspector who oversees every site inside its borders.
The appeals were heard within the same judicial circuit.
A judge assigned to that circuit handles cases from a dozen counties.
Similardistrict, jurisdiction
Note
The name remembers judges who traveled from town to town to hold court. The word survives even where nobody travels, because a circuit is the territory itself, with or without itinerant judges. It works as a map word rather than a journey word: a case is heard within a circuit, and a judge is assigned to one.
- 8Abbreviation of circuit court.
The dispute will be tried in the state circuit next month.
Appeals from the lower courts go up to the circuit.
Note
The short form stands for the court rather than its territory. A circuit court is one that sits at more than one place in the district it serves. Legal writing usually gives that full name first and then shrinks it, so a later sentence can say simply that the matter is now before the circuit.
- 9A group of movie theaters run as a single business under common ownership or management.
Like a supermarket chain, except each branch is a movie theater.
The new release was booked into every theater on the circuit.
A regional circuit picked up the independent film for a limited run.
Similarchain
Note
The cinema trade uses the same word as the stage did. Allen Eyles and Keith Skone's Cinemas of Hertfordshire (2002) mentions the head of "a separate circuit of cinemas," and a 1990 business case speaks of buying "a circuit of theaters." The usual phrasing is circuit of cinemas or theaters, with the owner named as running the circuit.
- 10A set of theaters among which the same performing acts travel in turn, common in the days of vaudeville.
Like a touring festival that visits the same set of venues year after year.
A popular dance act could earn good money working the circuit.
Bookers controlled which performers got slots on the major circuit.
Note
Vaudeville gave this sense its heyday: theaters were linked and booked as a unit, so one act could travel from house to house. The meaning is close to the chain of cinemas, but the difference matters. On a theater circuit the performers move, while on a cinema circuit it is the films that circulate.
- 11The enclosed space lying inside a circle or within a set of fixed boundaries.
Like the field enclosed by a running track: all the ground within the loop.
Within the circuit of the old walls lay the entire medieval town.
The festival filled the broad circuit of the market square.
Note
Here the word names the room inside the ring, not the ring. Shakespeare's Venus says she has hemmed Adonis "within the circuit of this ivory pale," and Milton's Paradise Lost (1667) has "a circuit wide enclosed with goodliest trees." The phrase within the circuit of is the natural frame, and it separates this sense from the encircling ring itself, which is the border rather than what it holds.
- 12
- 13A path through a graph that begins and ends at the same vertex without repeating any edge.
The algorithm searches for a circuit that returns to its starting vertex.
No edge repeats within a circuit, which sets it apart from an ordinary closed walk.
Note
Graph theorists are exact about what may repeat. In a circuit no edge is used twice, though the route may pass through the same vertex more than once. That separates it from a closed walk, which may reuse edges freely. A circuit is simply a trail that comes home.
- 14The basic administrative grouping of local Methodist churches gathered together as a single unit.
The Methodist circuit appointed a superintendent to oversee its congregations.
Several chapels in the circuit shared a single ordained minister.
Note
Methodism organizes itself from the circuit upward. Several neighboring congregations share one body of ministers, and circuits in turn sit within a wider district. The local society is the single congregation, while the circuit is the working unit above it. Ministers therefore serve a circuit rather than one chapel.
- 15A repeating thought that unconsciously cycles through a person's mind and exerts control over them.
Auditors claim a circuit can override a person's own intentions.
She described a circuit that looped endlessly through her mind.
Note
Scientology takes the word's idea of endless looping and applies it to the mind: the loop runs unnoticed and steers its owner. Outside that movement the word carries no such meaning. When writing about Scientology, attribute the term to the movement rather than presenting it as ordinary psychology.
- 16To travel around a place, making a journey that encircles it.
The bishop would circuit his diocese once a year to visit each parish.
Caravans circuited the desert oases along well-worn routes.
Note
Here the verb takes an object, the place gone round, as in "having circuited the air." Like the intransitive verb, it is obsolete. Where an older writer said he had circuited a place, modern English says he made a circuit of it, or simply that he circled or toured it.
- 17To move in a circle, going round and round; to circulate.
perpetual Motion keep, / Quick circuiting ; nor dare they close their Eyes
1708, [John Philips], CyderNote
No one now uses circuit as a verb of motion, but John Philips's Cyder (1708) has "perpetual Motion keep, / Quick circuiting." The verb takes no object: things circuit, but they do not circuit something. Today circle, revolve or circulate do the work. A writer who wants circuit itself should use the noun and say that something makes a circuit.
- 18An indirect, roundabout manner of expression; circumlocution.
The courtier's circuit of flattery delayed the true request.
They grew tired of his endless circuits and demanded a direct answer.
Note
Talk that goes round its subject instead of to it was once a circuit. The sense is long obsolete, surviving in old texts such as Huloet's Dictionarie of 1572, with its "circuite of words." In modern prose, use circumlocution or simply roundabout. A reader who meets circuit of words in an early text should take it as wordiness, not a route.
- 19One of the ten or so major provincial divisions of the Chinese empire from the Tang dynasty through the early Yuan.
A Tang circuit covered a vast territory made up of many prefectures.
Imperial inspectors toured the circuits to report on local governance.
Note
Under the Tang the word moved up a level. Instead of a frontier county, a circuit was one of about ten great provinces. A Tang circuit is therefore an enormous unit, and the dynasty named before it usually tells the reader which scale is meant.
- 20A major provincial division of China used from the Yuan dynasty through the early Republican period.
A Ming circuit grouped together numerous counties under one administration.
Officials were rotated among the circuits to discourage corruption.
- 21A county at the frontier of the empire, usually with a non-Chinese population, from the Han dynasty to the Western Jin.
A Han circuit on the western frontier governed mostly non-Chinese inhabitants.
The empire managed its border circuits with a lighter hand than the interior.
Note
Chinese history supplies this circuit, and its origin has nothing to do with the Latin "going round." It is a calque, a word-for-word rendering of Chinese 道 (dào) or 路 (lù). The term is strictly historical. Use it only of the past and with a dynasty attached, because the same English word covers several quite different Chinese divisions.
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Practice
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Origins
It came through Middle English and Old French circuit from Latin circuitus ('a going round'), from circuire ('to go round'), formed from circum ('around') plus ire ('to go').
It is a calque (a loan translation) of Chinese 道 (dào) or 路 (lù).