What English uses the word for
In current English the noun covers several jobs that still sit close together. It can be an opening worth taking, a degree of likelihood, luck treated as an impersonal force, or a risk someone decides to run. The adjective marks an unplanned encounter or result. The verb can mean to happen upon something, or to stake an outcome on uncertainty. All of those uses rest on one older picture: an event that falls out rather than being arranged.
The origin of the word chance is a French loan that English adopted near the end of the thirteenth century. Native Old English had other ways to talk about luck and what befalls a person; this particular noun is not one of them.
A French word for what falls
The immediate source is Old French cheance, already current in the twelfth century. In French it named accident, luck, fortune, a situation, and, quite literally, the falling of dice. English took the word through the French that remained a language of law, administration, and much written culture after the Norman settlement. Standard references treat it as a borrowing, not as a Germanic inheritance.
Middle English spellings wander: chance, chaunce, cheance, cheaunce, and still other shapes. That scatter is ordinary for the period and does not point to several different roots. The Middle English Dictionary groups the forms as one item from Old French. Dating is only slightly less tidy. The Oxford English Dictionary places the earliest English evidence in 1297, in Robert of Gloucester's Chronicle. Etymological handbooks often round the arrival to about 1300, and some dictionaries simply say the fourteenth century. Those figures describe the same late-medieval intake; they differ in how strictly a first quotation is counted.
In those early English uses the noun could mean something that takes place, especially an event outside human planning, and also a person's luck or lot, whether fair or harsh. Opportunity and randomness are already there in the first generations of record. Dice stay in view as well: a throw, a number that turns up, fortune as what the cubes decide.
From a Latin participle
French cheance is explained from a reconstructed Vulgar Latin form cadentia, that which falls or falls out. The reconstruction is marked as such because it is inferred from Romance descendants rather than quoted as a surviving classical lemma with that exact shape. It is built on Latin cadens, cadent-, the present participle of cadere, to fall. Latin already stretched that verb past gravity: to fall could also mean to befall, to happen, or to perish. Dice language makes the metaphor plain. What happens is what comes down.
The same participle later yields two more learned English doublets, cadence and cadenza, which arrived by another Romance route and kept a fall in the voice or in music rather than a fall of luck. Provençal cazensa and Italian cadenza belong to the same cluster. Modern French still has chance.
Behind cadere, comparativists reconstruct a Proto-Indo-European root commonly written kad- or with a palatal initial, meaning to fall. Notation differs across handbooks; the meaning does not. English chance has no direct Old English sibling from that root. What English does have is a large Latin family that entered by other paths: accident, case in the sense of how events fall out, casual, cascade, decay, incident, occasion. Further afield, Sanskrit preserves a verb of falling in the same family, and Armenian has a verb meaning to fall or become low. Those are kin of the Latin verb, not respellings of the English noun.
Senses that stayed, and one that faded
The history is not a simple climb from accident to opportunity. Opportunity and randomness are as old as the English record. What later speech mostly dropped is the plain sense of a mere occurrence, a thing that happens. For that job English now prefers event, happening, or incident. Around 1400 the noun is also used for fortuity itself: variability treated as a real agent, the lack of a cause that would make one outcome necessary.
Set phrases track the drift. To take one's chances, from the early fourteenth century, first meant to accept whatever happens. Main chance, from the 1570s, is the opening that offers the greatest advantage, and then the matter of most importance. The adjective chance, for something casual or unexpected, appears in the later seventeenth century. The verb chance meaning to happen is late fourteenth century; the sense to risk is much later, from the nineteenth.
A technical turn arrives in the eighteenth century. By 1778 the word is used for mathematical probability, the measurable likelihood of an outcome. That usage feeds the language of odds: a balanced prospect of gain or loss. To stand a chance is recorded from 1796. To take a chance or take chances first refers, around 1814, to joining a raffle, lottery, or game; the broader sense of running a risk follows in the 1820s.
The older gaming sense never quite vanished. A raffle ticket can still be called a chance, and talk of luck still borrows the fall of dice. In ordinary speech, though, the word now points to opportunity, likelihood, and risk far more often than to a bare event.
The sibling that kept the fall
A useful check on the story is cadence. Both nouns rest on falling. French and then English reserved chance for what befalls a person — luck, lots, later odds — while cadence kept a fall you can hear: the drop of a voice, the close of a musical phrase. The spellings look unrelated until the Latin participle is put back in place. That split is the most concrete leftover of the old metaphor. Fortune, like a die, is something that comes down.