14

14/24, or 585 parts per thousand. The commonest jewellery standard in the United States. The scale is karat with a K — a proportion of gold in an alloy — and is not the carat with a C used for gemstones, which is a unit of mass equal to 200 milligrams. A one-carat diamond and 24-karat gold have nothing in common but a homophone.

A fortnight — 14 days — remains everyday British and Commonwealth English usage, though the term is rare in American English, which more often says 'two weeks'.

There are 14 lines on the periodic table's lanthanide and actinide rows (chemistry). Each row holds fourteen elements because the f subshell holds fourteen electrons, which is why the table is drawn with two rows floating below it.

Carbon-14 has a half-life of about 5,730 years, which limits radiocarbon dating to roughly the last 50,000 years. Atmospheric weapons testing produced a spike used to date material formed after 1955.

The pH of the most alkaline end of the conventional scale is 14 (worldwide, dilute aqueous solutions at 25 degrees Celsius). The 0-to-14 range is a convention for dilute water solutions, not a limit: concentrated acids genuinely go below 0 and concentrated alkalis above 14. The scale is logarithmic, so each step is a tenfold change in hydrogen-ion concentration.

There are nearly 14 billion years of history since the Big Bang (worldwide, cosmology). The current figure is 13.8 billion years, derived from the Planck satellite's measurements of the cosmic microwave background rather than from any direct observation of the beginning.

There are 14 pounds in a stone (the United Kingdom and Ireland). Body weight is still commonly given in stones and pounds in both countries and almost nowhere else, including the United States, where the same weight is given in pounds alone.

14 is the atomic number of silicon, the element underlying modern semiconductor electronics.

14 February is Valentine's Day, observed in widely in Europe, the Americas and increasingly worldwide, with markedly different local customs. The date is the feast of Saint Valentine, a third-century martyr about whom almost nothing is reliably known. The romantic association is not ancient: it first appears in Geoffrey Chaucer's Parlement of Foules (c. 1382), which links the day to birds choosing mates. Customs differ sharply by country — in Japan and South Korea women traditionally give chocolate on 14 February, with a reciprocal White Day on 14 March.

14 is the fourth Catalan number (1, 1, 2, 5, 14, 42), the sequence that counts how many ways brackets can be validly nested and how many ways a polygon can be cut into triangles. It is separately the third square pyramidal number: 1 + 4 + 9, the count of balls in a square-based pyramid three layers deep.

In Catholic and Orthodox Christianity, the Stations of the Cross are traditionally numbered fourteen. The number settled in the seventeenth and eighteenth centuries. Earlier sets ranged from seven to more than thirty. Several stations have no direct scriptural source, which is why a fifteenth for the Resurrection, and an alternative scriptural set, are both in use. This is a scholarly account rather than the tradition's own framing.

Presented as belief or tradition, not as an established fact.