alpha

The English word alphabet came into Middle English from the Late Latin word alphabetum, which in turn originated in the Greek ἀλφάβητος ( alphabētos ), from alpha and beta, the first two letters of the Greek alphabet.

The word " alphabet " in English has a source in Greek language in which the first two letters were " A " ( alpha ) and " B " ( beta ), hence " alphabeta ".

In the subsurface environment, it is also produced through neutron capture by or alpha emission by calcium.

The crystal lattice of solid americium and its compounds contains intrinsic defects, which are induced by self-irradiation with alpha particles and accumulate with time ; this results in a drift of some material properties.

The second longest-lived isotope of astatine, astatine-211, is the only one currently having any commercial application, being employed in medicine to diagnose and treat some diseases via its emission of alpha particles ( helium-4 nuclei ).

In 1909, Hans Geiger and Ernest Marsden, under the direction of physicist Ernest Rutherford, bombarded a sheet of gold foil with alpha rays — by then known to be positively charged helium atoms — and discovered that a small percentage of these particles were deflected through much larger angles than was predicted using Thomson's proposal.

In English the noun alpha is used as a synonym for " beginning ", or " first " ( in a series ), reflecting its Greek roots.

In Ancient Greek, alpha was pronounced when short and when long.

Where there is ambiguity, long and short alpha are sometimes written with a macron and breve today: Ᾱᾱ, Ᾰᾰ.

In Modern Greek, vowel length has been lost, and all instances of alpha represent the short.

In the polytonic orthography of Greek, alpha, like other vowel letters, can occur with several diacritic marks: any of three accent symbols (), and either of two breathing marks (), as well as combinations of these.

In the Attic-Ionic dialect of Ancient Greek, long alpha fronted to ( eta ).

In Doric and Aeolic, long alpha is preserved in all positions.

The letter alpha represents various concepts in physics and chemistry, including alpha radiation, angular acceleration, alpha particles, alpha carbon and strength of electromagnetic interaction ( as Fine-structure constant ).

Furthermore, in mathematics, the letter alpha is used to denote the area underneath a normal curve in statistics to denote significance level when proving null and alternative hypotheses.

The proportionality operator "∝" ( in Unicode: U + 221D ) is sometimes mistaken for alpha.

The uppercase letter alpha is not generally used as a symbol because it tends to be rendered identically to the uppercase Latin A.

In the International Phonetic Alphabet, a letter based on the lower case of alpha represents the open back unrounded vowel.

Plutarch, in Moralia, presents a discussion on why the letter alpha stands first in the alphabet.

Ammonius asks Plutarch what he, being a Boeotian, has to say for Cadmus, the Phoenician who reputedly settled in Thebes and introduced the alphabet to Greece, placing alpha first because it is the Phoenician name for ox — which, unlike Hesiod, the Phoenicians considered not the second or third, but the first of all necessities.

For Lamprias had said that the first articulate sound made is " alpha ", because it is very plain and simple — the air coming off the mouth does not require any motion of the tongue — and therefore this is the first sound that children make.

According to Plutarch's natural order of attribution of the vowels to the planets, alpha was connected with the Moon.