noun, plural H’s or Hs, h’s or hs.
- the eighth letter of the English alphabet, a consonant.
- any spoken sound represented by the letter H or h, as in hot or behave.
- something having the shape of an H.
- a written or printed representation of the letter H or h.
- a device, as a printer’s type, for reproducing the letter H or h.
- the eighth in order or in a series.
- (sometimes lowercase) the medieval Roman numeral for 200.Compare Roman numerals.
- Chemistry. hydrogen.
- Biochemistry. histidine.
- horizontal component of the earth’s magnetic field.
- magnetic intensity.
- Music. the letter used in German to indicate the tone B.
- hour; hours.
- heavy sea.
- Baseball. hit; hits.
- Also hr. hour; hours.
- (in prescriptions) an hour.
- the seventh letter of the Greek alphabet (H, η).
- the vowel sound represented by this letter.
noun plural h’s, H’s or Hs
- the eighth letter and sixth consonant of the modern English alphabet
- a speech sound represented by this letter, in English usually a voiceless glottal fricative, as in hat
- something shaped like an H
- (in combination)an H-beam
- physics Planck constant
- chess See algebraic notation
- chem hydrogen
- magnetic field strength
- electronics henry or henries
- thermodynamics enthalpy
- (on Brit pencils, signifying degree of hardness of lead) hardH; 2H; 3H Compare B (def. 9)
- slang heroin
- Hungary (international car registration)
- the seventh letter in the Greek alphabet (Η, η), a long vowel sound, transliterated as e or ē
noun plural eta or etas
- (in Japan, formerly) a member of a class of outcasts who did menial and dirty tasks
- estimated time of arrival
n acronym for
- Euzkadi ta Askatsuna: an organization of militant Basque nationalists attempting to gain independence for the Basques, esp those ruled by Spain, until a ceasefire in 1998, by means of guerrilla warfare
the pronunciation “aitch” was in Old French (ache “name of the letter H”), and is from a presumed Late Latin *accha (cf. Italian effe, elle, emme), with the central sound approximating the value of the letter when it passed from Roman to Germanic, where it at first represented a strong, distinctly aspirated -kh- sound close to that in Scottish loch. In earlier Latin the letter was called ha.
In Romanic languages, the sound became silent in Late Latin and was omitted in Old French and Italian, but it was restored in Middle English spelling in words borrowed from French, and often later in pronunciation, too. Thus Modern English has words ultimately from Latin with missing -h- (e.g. able, from Latin habile); with a silent -h- (e.g. heir, hour); with a formerly silent -h- now often vocalized (e.g. humble, humor, herb); and even a few with an excrescent -h- fitted in confusion to words that never had one (e.g. hostage, hermit).
Relics of the formerly unvoiced -h- persist in pedantic insistence on an historical (object) and in obsolete mine host. The use in digraphs (e.g. -sh-, -th-) goes back to the ancient Greek alphabet, which used it in -ph-, -th-, -kh- until -H- took on the value of a long “e” and the digraphs acquired their own characters. The letter passed into Roman use before this evolution, and thus retained there more of its original Semitic value.
- The symbol forPlanck’s constant
- The symbol for the elementhydrogen
- The seventh letter of the Greek alphabet.
- Abbreviation of height
- The symbol for Planck’s constant.
- The symbol for henry.
- The symbol for hydrogen.
- The lightest and most abundant element in the universe, normally consisting of one proton and one electron. It occurs in water in combination with oxygen, in most organic compounds, and in small amounts in the atmosphere as a gaseous mixture of its three isotopes (protium, deuterium, and tritium) in the colorless, odorless compound H2. Hydrogen atoms are relatively electropositive and form hydrogen bonds with electronegative atoms. In the Sun and other stars, the conversion of hydrogen into helium by nuclear fusion produces heat and light. Hydrogen is used to make rocket fuel, synthetic ammonia, and methanol, to hydrogenate fats and oils, and to refine petroleum. The development of physical theories of electron orbitals in hydrogen was important in the development of quantum mechanics. Atomic number 1; atomic weight 1.00794; melting point -259.14°C; boiling point -252.8°C; density at 0°C 0.08987 gram per liter; valence 1. See Periodic Table. See Note at oxygen.