2h

symbol, chemistry
deuterium.
also, 2h, hb.
h
/eɪtʃ/
noun (pl) h’s, h’s, 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

h
symbol
(physics) planck constant
hecto-
(chess) see algebraic notation
h
symbol
(chem) hydrogen
(physics)

magnetic field strength
hamiltonian

(electronics) henry or henries
(thermodynamics) enthalpy
(on brit pencils, signifying degree of hardness of lead) hard: h, 2h, 3h compare b (sense 9)
(slang) heroin
abbreviation
hungary (international car registration)
h

the pr-nunciation “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 p-ssed 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 pr-nunciation, 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 p-ssed into roman use before this evolution, and thus retained there more of its original semitic value.

h abbr.
the symbol for planck’s constant..

h
the symbol for the element hydrogen.
h

abbreviation of height

the symbol for planck’s constant.

h

the symbol for henry.

the symbol for hydrogen.

noun

heroin (narcotics)
related terms

big h

height
hour
planck’s constant

enthalpy
hamiltonian
handicapped accessible
haze
henry
heroin
hispanic
hit
humidity
hungary (international vehicle id)
hydrogen