Wiktionary

hydrogen

English

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WOTD – 7 February 2026
Chemical element (edit)
H
Atomic number 1
hydrogen
Classification data
Period 1
Group 1
Block s-block
Class nonmetal
Previous: —
Next: helium (He) →
English Wikipedia article on Hydrogen
 
Hydrogen in a plasma state in a discharge tube, glowing purple as an electric current is passed through it.

Etymology

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Etymology tree
Proto-Indo-European *wed-
Proto-Indo-European *-r̥
Proto-Indo-European *wódr̥
Proto-Hellenic *údōr
Ancient Greek ῡ̆̔́δωρ (hū̆́dōr)
Ancient Greek ὑδρο- (hudro-)lbor.
French hydro-
Proto-Indo-European *ǵenh₁-
Proto-Indo-European *-os
Proto-Indo-European *ǵénh₁os
Proto-Hellenic *génos
Ancient Greek γένος (génos)
Proto-Indo-European *-os
Proto-Indo-European *-ēs
Ancient Greek -ης (-ēs)
Ancient Greek -γενής (-genḗs)lbor.
French -gène
French hydrogènebor.
English hydrogen

    Borrowed from French hydrogène (“hydrogen”), coined by the French chemists Louis-Bernard Guyton de Morveau (1737–1816) and Antoine Lavoisier (1743–1794) from hydro- (prefix meaning ‘water’) + -gène (suffix denoting a producer of something),[1] from the fact that water is produced as a compound when hydrogen is oxidized.

    By surface analysis, hydro- (prefix meaning ‘water’) +‎ -gen (suffix denoting a producer of something).

    Pronunciation

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    Noun

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    hydrogen (countable and uncountable, plural hydrogens) (chemistry)

    2. (uncountable) The lightest chemical element (symbol H), with an atomic number of 1 and atomic weight of 1.008.
      Alternative form: H (symbol)
      Our professor then reminded us that a hydrogen ion is merely a proton, and thus we should think about acid-base theory as we consider this problem further.
      • 1791, [Erasmus Darwin], “Canto I”, in The Botanic Garden; a Poem, in Two Parts. […], London: J[oseph] Johnson, […], →OCLC, part I (The Economy of Vegetation), footnote, page 18:
        The ignis fatuus or Jack a lantern, ſo frequently alluded to by poets, is ſuppoſed to originate from the inflammable air, or Hydrogene, given up from moraſſes; […]
      • 1820, Sophocles, “Œdipus Tyrannus; or, Swellfoot the Tyrant. A Tragedy, in Two Acts. […]”, in Percy Bysshe Shelley, transl., edited by [Mary] Shelley, The Poetical Works of Percy Bysshe Shelley. […], new edition, London: Edward Moxon […], published 1840, →OCLC, Act I, page 184:
        But my Leech—a leech / Fit to suck blood, with lubricous round rings, / Capaciously expatiative, which make / His little body like a red balloon, / As full of blood as that of hydrogen, / Sucked from men's hearts; […]
      • 1827, Edward Turner, “Section IV. Hydrogen.”, in Elements of Chemistry: Including the Recent Discoveries and Doctrines of the Science, Edinburgh: […] William Tait, […]; and Charles Tait, […], part II (Inorganic Chemistry), page 160:
        Water is the sole product of the combustion of hydrogen gas. For this important fact we are indebted to Mr. [Henry] Cavendish. He demonstrated it by burning oxygen and hydrogen gases in a dry glass vessel, when a quantity of pure water was generated exactly equal in weight to that of the gases which had disappeared.
      • 1997, Ian McEwan, chapter 1, in Enduring Love, [United Kingdom]: The Softback Preview, →OCLC, page 3:
        It was an enormous balloon filled with helium, that elemental gas forged from hydrogen in the nuclear furnace of the stars, first step along the way in the generation of multiplicity and variety of matter in the universe, including our selves and all our thoughts.
      1. (countable) An atom of this element.
        Each carbon of the ring has one hydrogen attached except for the fourth one, which is bonded to a substituent.
        • 1920 July, Wendell M[itchell] Latimer, Worth H. Rodebush, “Polarity and Ionization from the Standpoint of the Lewis Theory of Valence”, in Arthur B. Lamb, editor, The Journal of the American Chemical Society, volume XLII, number 7, Easton, Pa.: Eschenbach Printing Company [for the American Chemical Society], →ISSN, →OCLC, page 1431:
          Water occupies an intermediate position and shows tendencies both to add and give up hydrogen, which are nearly balanced. Then, in terms of the Lewis theory, a free pair of electrons on one water molecule might be able to exert sufficient force on a hydrogen held by a pair of electrons on another water molecule to bind the two molecules together.
        • 1995, William H. Brown, “Alkanes and Cycloalkanes”, in Organic Chemistry, Fort Worth, Tex.; Philadelphia, Pa.: Saunders College Publishing; Harcourt Brace College Publishers, →ISBN, page 62:
          [H]ydrogens are also classified as primary, secondary, or tertiary depending on the type of carbon to which each is bonded. Those attached to primary carbons are classified as primary hydrogens, those on secondary carbons are secondary hydrogens, and those on tertiary carbons are tertiary hydrogens. Hydrogen atoms in a compound can be divided into equivalent sets. Equivalent hydrogens have the same chemical environment. A direct way to determine which hydrogens in a molecule are equivalent is to replace each in turn by a "test atom," as for example a halogen atom.
    4. (uncountable) Molecular hydrogen (sense 1; symbol H2), a colourless, odourless and flammable gas at room temperature.
      A large tank of hydrogen constituted most of the bulk of that rocket.
      • 1845 February 8, “Balloons”, in Theodore Dwight, Jr., editor, American Penny Magazine, and Family Newspaper, volume I, number 1, New York, N.Y.: Express Office, […], →ISSN, →OCLC, page 12, column 1:
        [Jacques] Charles was the first to send up a hydrogen balloon, 12 feet in diameter, which rose 3,123 feet, disappeared in the clouds, and fell at the distance of 15 miles.
      • 1991 August, Stanley E. Spangler, “Kennan, Containment, and Carrots”, in Force and Accommodation in World Politics, Maxwell Air Force Base, Ala.: Air University Press, →ISBN, part 1 (Factors Inhibiting Accommodative Diplomacy since World War II), pages 32–33:
        As the tension between the Soviets and the United States increased from 1948 to 1950, the administration took a number of actions that [George Frost] Kennan felt narrowed the possibilities for constructive negotiations between the two nations. These actions included the decisions to build the hydrogen bomb, to maintain American troops in Japan after the formal occupation was over, to create an independent West German state, and to form the North Atlantic Treaty Organization (NATO).
      • 2005, F. W. Petersen, S. E. T. Bullock, “Sustainable Development Indicators—Some Technological Changes Made in the South African Mining and Resources Sector to Meet the Challenge”, in Roberto C[errini] Villas-Bôas [et al.], editors, A Review on Indicators of Sustainability for the Minerals Extraction Industries, Rio de Janeiro, Brazil: CETEM/CNPq/CYTED, →ISBN, part 2 (Indicators: Some Facts, Exercises and Proposals), page 162:
        To this end the Department of Science and Technology has identified the hydrogen economy and related fuel cell technologies as a "Frontier Science and Technology Area" that could potentially change the innovation course of the country's natural resources, and yield multiple social and economic benefits.
      1. (countable) A molecule of this molecular species.
    6. (uncountable) Synonym of protium (“the lightest and most common isotope of hydrogen (sense 1; symbol H, 1H, or 11H), as contrasted with deuterium and tritium”).
      Both hydrogen and deuterium are present in every glass of water that you drink, but the amount of deuterium is rather small.
      • 1969 September, Dumas A. Otterson, Robert J. Smith, “Introduction”, in Absorption of Hydrogen by Palladium and Electrical Resistivity up to Hydrogen-Palladium Atom Ratios of 0.97 (NASA Technical Note; D-5441), Washington, D.C.: National Aeronautics and Space Administration, →OCLC, page 2:
        Hydrogen is generally considered to be electronically the same as deuterium. […] Neutron diffraction experiments by Ferguson, Schindler, Tanaka, and Morita (ref. 4) revealed that, near 50K, some hydrogen had moved from interstitial octahedral sites (0, 0, 1/2; 1/2, 0, 0; …) of the palladium lattice to the tetrahedral sites (1/4, 1/4, 1/4; 3/4, 3/4; …) (O-T transitions).

    Synonyms

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    element
    molecule

    Hyponyms

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    isotopes
    molecule

    Derived terms

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    Descendants

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    • → Burmese: ဟိုက်ဒရိုဂျင် (huikda.ruigyang)

    Translations

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    See also

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    Periodic table of elements in English · periodic table of elements (layout · text)
    Period
    Group
    		 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
    1 1   H
    hydrogen     		Color of the number (state of matter at STP): liquid, gas, solid, synthetic, not yet been discovered 2   He
    helium
    2 3   Li
    lithium     		4   Be
    beryllium     		Blocks: d-block f-block p-block s-block 5   B
    boron     		6   C
    carbon     		7   N
    nitrogen     		8   O
    oxygen     		9   F
    fluorine     		10   Ne
    neon
    3 11   Na
    sodium     		12   Mg
    magnesium     		13   Al
    aluminum     		14   Si
    silicon     		15   P
    phosphorus     		16   S
    sulfur     		17   Cl
    chlorine     		18   Ar
    argon
    4 19   K
    potassium     		20   Ca
    calcium
    		21   Sc
    scandium     		22   Ti
    titanium     		23   V
    vanadium     		24   Cr
    chromium     		25   Mn
    manganese     		26   Fe
    iron     		27   Co
    cobalt     		28   Ni
    nickel     		29   Cu
    copper     		30   Zn
    zinc     		31   Ga
    gallium     		32   Ge
    germanium     		33   As
    arsenic     		34   Se
    selenium     		35   Br
    bromine     		36   Kr
    krypton
    5 37   Rb
    rubidium     		38   Sr
    strontium
    		39   Y
    yttrium     		40   Zr
    zirconium     		41   Nb
    niobium     		42   Mo
    molybdenum     		43   Tc
    technetium     		44   Ru
    ruthenium     		45   Rh
    rhodium     		46   Pd
    palladium     		47   Ag
    silver     		48   Cd
    cadmium     		49   In
    indium     		50   Sn
    tin     		51   Sb
    antimony     		52   Te
    tellurium     		53   I
    iodine     		54   Xe
    xenon
    6 55   Cs
    cesium     		56   Ba
    barium     		*
    		 71   Lu
    lutetium     		72   Hf
    hafnium     		73   Ta
    tantalum     		74   W
    tungsten     		75   Re
    rhenium     		76   Os
    osmium     		77   Ir
    iridium     		78   Pt
    platinum     		79   Au
    gold     		80   Hg
    mercury     		81   Tl
    thallium     		82   Pb
    lead     		83   Bi
    bismuth     		84   Po
    polonium     		85   At
    astatine     		86   Rn
    radon
    7 87   Fr
    francium     		88   Ra
    radium     		**
    		 103   Lr
    lawrencium     		104   Rf
    rutherfordium     		105   Db
    dubnium     		106   Sg
    seaborgium     		107   Bh
    bohrium     		108   Hs
    hassium     		109   Mt
    meitnerium     		110   Ds
    darmstadtium     		111   Rg
    roentgenium     		112   Cn
    copernicium     		113   Nh
    nihonium     		114   Fl
    flerovium     		115   Mc
    moscovium     		116   Lv
    livermorium     		117   Ts
    tennessine     		118   Og
    oganesson

    * lanthanides 57   La
    lanthanum     		58   Ce
    cerium     		59   Pr
    praseodymium     		60   Nd
    neodymium     		61   Pm
    promethium     		62   Sm
    samarium     		63   Eu
    europium     		64   Gd
    gadolinium     		65   Tb
    terbium     		66   Dy
    dysprosium     		67   Ho
    holmium     		68   Er
    erbium     		69   Tm
    thulium     		70   Yb
    ytterbium
    ** actinides 89   Ac
    actinium     		90   Th
    thorium     		91   Pa
    protactinium     		92   U
    uranium     		93   Np
    neptunium     		94   Pu
    plutonium     		95   Am
    americium     		96   Cm
    curium     		97   Bk
    berkelium     		98   Cf
    californium     		99   Es
    einsteinium     		100   Fm
    fermium     		101   Md
    mendelevium     		102   No
    nobelium

    References

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    1. ^ Compare “hydrogen, n.”, in OED Online  ⁠, Oxford: Oxford University Press, September 2024; “hydrogen, n.”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.

    Further reading

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    Danish

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    Danish Wikipedia has an article on:
    Wikipedia da
    Chemical element (edit)
    H
    Atomic number 1
    hydrogen
    Alternative names: brint
    Classification data
    Period 1
    Group 1
    Block s-block
    Class nonmetal
    Previous: —
    Next: helium (He) →

    Etymology

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    From French hydrogène.

    Noun

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    hydrogen n (singular definite hydrogenet, not used in plural form)

    1. hydrogen
      Synonym: brint

    Declension

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    Declension of hydrogen
    neuter
    gender     		singular
    indefinite definite
    nominative hydrogen hydrogenet
    genitive hydrogens hydrogenets

    References

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    Norwegian Bokmål

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    Chemical element (edit)
    H
    Atomic number 1
    hydrogen
    Classification data
    Period 1
    Group 1
    Block s-block
    Class nonmetal
    Previous: —
    Next: helium (He) →
    Norwegian Wikipedia has an article on:
    Wikipedia no

    Noun

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    hydrogen n (definite singular hydrogenet) (uncountable)

    1. hydrogen (chemical element, symbol H)

    Derived terms

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    Norwegian Nynorsk

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    Chemical element (edit)
    H
    Atomic number 1
    hydrogen
    Classification data
    Period 1
    Group 1
    Block s-block
    Class nonmetal
    Previous: —
    Next: helium (He) →
    Norwegian Nynorsk Wikipedia has an article on:
    Wikipedia nn

    Noun

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    hydrogen n (definite singular hydrogenet) (uncountable)

    1. hydrogen (chemical element, symbol H)

    Derived terms

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    Welsh

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    Chemical element (edit)
    H
    Atomic number 1
    hydrogen
    Classification data
    Period 1
    Group 1
    Block s-block
    Class nonmetal
    Previous: —
    Next: heliwm (He) →
    Welsh Wikipedia has an article on:
    Wikipedia cy

    Etymology

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    Borrowed from English hydrogen, from French hydrogène, from Ancient Greek ὕδωρ (húdōr, “water”) + γεννάω (gennáō, “to bring forth”).

    Pronunciation

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    Noun

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    hydrogen m (uncountable, not mutable)

    1. hydrogen
      Synonyms: ulai, ulnwy

    Derived terms

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    Further reading

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    • R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “hydrogen”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies
    Retrieved from "https://en.wiktionary.org/w/index.php?title=hydrogen&oldid=90515819"