A bowl cut into a mountain
On a high ridge the word names a landform more often than a building. A cirque is a steep-walled hollow in a mountainside, usually at the blunt head of a valley, open downhill and cupped on the other sides by cliffs. Ice once sat in that basin and scoured it. When the ice has gone, the floor is often overdeepened, and a small round lake, a tarn, may sit behind a lip of bedrock or a dam of till. English geology also uses corrie and cwm for the same kind of amphitheatre, depending on whether the writer’s training runs through Scotland or Wales. Outside that technical sense the word still appears in literary English for a ring or a circlet, but that use is thin. The touring show under canvas is a circus, a close relative, not a synonym.
The origin of the word cirque is a French loan that English took in around 1600.
Borrowed from French, not grown at home
French cirque is recorded from the fourteenth century. It named a circular arena, the sort of unroofed space Romans had used for races and public spectacle. English borrowed that French form near the turn of the seventeenth century. Merriam-Webster dates the first English use to 1601. Other dictionaries give a window of 1595 to 1605. Oxford’s learner dictionary puts the early English sense later still, in the late seventeenth century, and treats it first as a ring or circlet rather than as an arena. The calendars differ by a few decades; the meanings sit next to each other. What is not in doubt is the path. The French noun comes from Latin circus, a ring or circular line, a word Romans also applied to their racing grounds, above all the Circus Maximus.
Circus itself had already entered English in the late fourteenth century, taken straight from Latin rather than through French. Cirque and circus are therefore doublets: two English words from one Latin source, arriving by different routes and settling into different jobs. Italian and Spanish keep circo for the arena. French kept cirque for both the show-place and, later, the mountain basin. English split the labor. When modern English wants a French flavor for circus arts, it sometimes borrows cirque back as a styling, but the established English noun is the landform.
A Latin ring and a Greek neighbor
Latin circus is the whole word English received. There is no native prefix to peel off once the loan is in place. The French spelling is Latin circus adjusted to French sound and ending, then taken over as a unit.
Behind the Latin form sits a Greek neighbor, kirkos, a circle or ring, also used of a racecourse. Whether Latin borrowed the Greek word or the two are cognates is not settled. Many etymologists place both in a reconstructed Proto-Indo-European family meaning to turn or to bend, the same background often given for Latin curvus and, more loosely, for English curve and circle. That deeper step is a reconstruction, not a dated citation, and it should stay in the background. The documented chain is shorter: Latin ring-word, French arena-word, English borrowing.
Cognates and cousins make the ring visible across languages. French cirque, Italian circo, Spanish circo, and English circus all point at the same Latin noun. Circle and circuit reached English by other Latin routes, through circulus and circuitus, and they share the older idea of going round. They are relatives, not the same loan.
From arena to amphitheatre of ice
The English senses shifted in two stages. First, the arena reading faded. Dictionaries now mark cirque as circus as archaic. It is a historical label, useful in older prose and in talk of Roman buildings, not on a poster for acrobats. The circular sense lasted longer in literary English: tents around a dusty cirque, a moon described as a glowing cirque. That is the Latin ring still showing through.
The second shift is the one that matters in modern English. In 1823 Jean de Charpentier, writing on the rocks of the Pyrenees, used French cirque for semicircular mountain basins. He was naming a shape, an amphitheatre in stone, not yet pinning the hollow to a single process. In 1860 the British geologist A. C. Ramsay tied such basins to ice. English scientific papers were discussing cirques by the early 1870s. T. G. Bonney’s 1871 paper on their formation still argued that running water, not glaciers, had done the cutting. The glacial reading won for the classic alpine examples, but the word itself stayed descriptive: a depression open downslope, walled elsewhere by steep arcuate cliffs, with a floor gentler than the headwall. Ice explains most textbook cases. Water-cut amphitheatres, including some karst and volcanic basins, have been called cirques as well, which is why some geomorphologists say glacial cirque when the ice history is the point.
Regional names never vanished. Scottish Gaelic coire, a cauldron, gave English corrie. Welsh cwm, a valley, gave cwm. German Kar, Norwegian botn, and Spanish circo or hoyo name the same kind of hollow in other languages. English geology preferred the French word, perhaps because it already meant a built amphitheatre and the landform looks like one. Neighboring cirques that eat toward each other leave a sharp ridge, an arête; three or more can leave a pyramidal peak. The vocabulary of high ice still leans on French.
The ring the mountain kept
The durable fact is visual. A Latin word for a ring, filtered through French, now labels a mountain bowl that ice, not architects, carved into a natural circus. The show-place and the landform share a shape: a space enclosed on most sides, open on one, meant to hold motion in a curve. English simply gave the two jobs to two doublets, and left cirque on the map.