1,000

In 1000, Stephen I was crowned first king of Hungary, binding the Magyar realm to Latin Christendom (Hungary).

In 1000, Norse voyagers under Leif Erikson reached Vinland on the North American coast, five centuries before any other European landfall (North Atlantic).

Anticipation of the millennium in the year 1000 is often described as widespread panic. Modern scholarship finds the evidence thin and largely retrospective, and most contemporaries did not count years in a way that made the date meaningful.

A kilobyte was long taken to mean 1,024 bytes, and standards bodies later defined kilo as exactly 1,000 with kibi for the binary value. Storage is sold in decimal and reported in binary, which is where the missing capacity goes.

Gigabit Ethernet is standardised as 1000BASE-T, running at 1,000 megabits per second over twisted pair. Network speeds are one of the few places in computing where the prefixes are decimal throughout and mean what SI says they mean — a gigabit is 10⁹ bits, never 2³⁰ — which is a large part of why a connection quoted in gigabits never quite delivers the file-size-per-second a reader expects when file sizes are reported in binary units.

Metric prefixes advance in factors of a thousand rather than a hundred, which is why kilo, mega and giga are three orders apart. The spacing was chosen to match the range over which quantities are actually compared.

'A grand' is a long-standing English-language slang term for exactly 1000 units of currency (dollars, pounds, or otherwise), in use since at least the early 20th century.

A billion means 10⁹ on the short scale and 10¹² on the long scale, and the difference is a thousandfold. The short scale advances by factors of a thousand — million, billion, trillion — while the long scale advances by factors of a million and inserts 'milliard' at 10⁹. The United Kingdom used the long scale until the Treasury adopted the short scale for official statistics in 1974; much of continental Europe and Latin America still uses the long one. Any figure quoted as 'a billion' without a source is ambiguous by a factor of a thousand.

In English-language popular usage, the saying that a picture is worth a thousand words is routinely attributed to a Chinese or Japanese proverb. It is an American advertising coinage: Fred R. Barnard used it in the trade press in the 1920s and himself called it a Chinese proverb so that people would take it seriously. No earlier Chinese source has been found. This is a scholarly account rather than the tradition's own framing.

There are 1000 millimetres in a metre, and metres in a kilometre (worldwide, SI). The decimal step is the whole point of the system: converting between metric units moves a decimal point, where converting between imperial ones requires remembering 12, 3, 22, 220 and 8.

The SI prefix 'kilo-' means ×1000 — a kilogram is 1000 grams and a kilometre is 1000 metres — making 1000 the foundational scaling factor for the International System of Units' most commonly used multiples.

Revelation 20 describes a reign of a thousand years, and the interpretations of that period divide Christian traditions into named positions — premillennial, postmillennial and amillennial — according to whether the thousand years is read as a future literal period, a present symbolic one, or something else again. The word 'millennium' in its ordinary calendar sense descends from this passage. The disagreement is doctrinal and long-running; the text's use of the figure is the documented part.

1,000 is 10³, and that is why the metric prefixes step in thousands rather than hundreds: each step up is one more factor of ten applied three times, so a cubic metre is exactly a thousand litres and a tonne is exactly a thousand kilograms. The same cube relationship is why converting a volume between metric units moves the decimal point three places at a time while converting a length moves it one.