Longman Dictionary of Contemporary English
Douglas Harper's Etymology Dictionary
Wiktionary
a. 1 So many as to be incapable of being counted. 2 (context mathematics English) Incapable of being put into one-to-one correspondence with the natural numbers or any subset thereof. 3 (context grammar of a noun English) Describes a meaning of a noun that cannot be used freely with numbers or the indefinite article, and which therefore takes no plural form. Example: ''information''. n. (context linguistics English) An uncountable noun.
Wikipedia
Usage examples of "uncountable".
Among the uncountable stars, Alpha and Beta Crucis burned bright enough to join the moons in casting shadows.
Volcanoes dormant for uncountable millennia suddenly rumbled into full, frightful, fiery life all along the chains of eastern and southern mountains, darkening days with their wind-borne dust and ash, belching molten lava and superheated stones to fire hundreds of square miles of montane forests.
Arabic, innumerable Indian dialects, Hebrew, Pehlevi, Assyrian, Babylonian, Mongolian, Chinese, Burmese, Mesopotamian, Javanese: the list of philological works considered Orientalist is almost uncountable.
As he had said, it was large, polyhedral, shiny although dulled by uncountable scratches.
Intellectually, the libraries and active mental configurations of the Sophotech segment of the population embodied uncountable quadrillions of units of information, infinitesimal processing times and nonsequential semantic and symbolic arrangements no human mind, no matter how augmented, could understand.
Illinois has also always been known for its uncountable number of tiny, shittily maintained, shoulderless rural highways, against and alongside which corn grows quickly and thickly and tall.
The world had swinked, and looped its wild orbit for uncountable ages, all to produce this latest moment of lucid afternoon: and yet what cause was there for mirth?
When he had won uncountable thousands of credits the doors of the Penny Palace closed and the roly-poly man came over and spoke curtly.
Arabic, innumerable Indian dialects, Hebrew, Pehlevi, Assyrian, Babylonian, Mongolian, Chinese, Burmese, Mesopotamian, Javanese: the list of philological works considered Orientalist is almost uncountable.
Two farmers were emigrating downriver from Illinois, in search of milder climate, and had brought with them a team of plow horses, two milk cows, numerous pigs, uncountable chickens in crates, farm machinery, household furniture, wives, invalid grandfolks and what sometimes seemed to be about two hundred children.
Right out there were the meteors, uncountable thousands of millions of them, and a certain proportion of them carried values.
The Dutch-style row houses had been chopped into pieces and misused as rooming houses for men with hot plates and ashtrays and racing forms, or floor-through apartments, where sprawling families of cousins were crammed into each level, their yards and stoops teeming with uncountable children.
I had bred, broken, and rebroken uncountable race horses in Australia, but Sparking Plug was the only good one I had so far ridden in England, and I was interested to see how he compared.
The survivors of Bravo Company—all twelve of them—and the remaining two hundred and ninety members of The Basik's Own, pitted against one hundred and twenty star systems, with a population right at three-quarters of a trillion humans, and uncountable soldiers and ships.
From above the dull metal plating of the machine an uncountable profusion of chromatically coloured tubes ran towards the distant roof.