noun · verb · 4 senses · updated from the 2026-07-25 local source snapshot
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
Sound
Pronunciation
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Received-Pronunciation:/ˈɹeɪ.dɪ.əm/
General-American:rād'ēəm
General-American:/ˈɹeɪ.di.əm/
UK:Recorded audio is listed in the source snapshot.
General-American:Recorded audio is listed in the source snapshot.
CMU ARPABET:R EY1 D IY0 AH0 M
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
noun
Meaning 1
The chemical element (symbol Ra) with an atomic number of 88. It is a soft, shiny and silvery radioactive alkaline earth metal.
Definition source: English Wiktionary via Wiktextract
Usage: countable, uncountable
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
2
noun
Meaning 2
A type of cloth woven from silk or synthetic yarn, often with a shiny appearance.
Definition source: English Wiktionary via Wiktextract
Usage: countable, dated, uncountable
Topics: business, manufacturing, textiles
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
3
verb
Meaning 3
To treat (a tumour, etc.) with radium.
Definition source: English Wiktionary via Wiktextract
Usage: ambitransitive, obsolete
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: radiumize
Antonyms: none provided
4
noun
Meaning 4
an intensely radioactive metallic element that occurs in minute amounts in uranium ores
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: Ra, atomic number 88
Antonyms: none provided
Broader terms: metallic element, metal
History
Etymology
Etymology tree Latin radiusder. French radio- Proto-Indo-European *h2eǵ- Proto-Indo-European *-eti Proto-Indo-European *h2éǵeti Proto-Italic *agō Latin agō Proto-Indo-European *-wós Proto-Indo-European *-iHwósder. Latin -īvus ▲ Ancient Greek ἐνεργητῐκός (energētĭkós)sl. Latin āctīvusbor. Old French actif French actif French radio(actif) Proto-Indo-European *-(i)yós Proto-Italic *-ijos Proto-Italic *-ios Old Latin -ios Latin -ius Latin -ium French radiumbor. English radium Borrowed from French radium, from rad(ioactif) (“radioactive”) + -ium (suffix used to form the names of metallic elements).
Across languages
Translations
55 source translations are retained for this English entry.
Afrikaans:
radium
— chemical element with an atomic number of 88
Arabic:
رَادِيُوم
(rādiyūm)
— chemical element with an atomic number of 88
Armenian:
ռադիում
(ṙadium)
— chemical element with an atomic number of 88
Asturian:
radiu
— chemical element with an atomic number of 88
Breton:
radiom
— chemical element with an atomic number of 88
Bulgarian:
радий
(radij)
— chemical element with an atomic number of 88
Burmese:
ရေဒီယမ်
(rediyam)
— chemical element with an atomic number of 88
Catalan:
radi
— chemical element with an atomic number of 88
Chinese Cantonese:
鐳 /镭
(leoi4)
— chemical element with an atomic number of 88
Chinese Mandarin:
鐳 /镭
(léi)
— chemical element with an atomic number of 88
Czech:
radium
— chemical element with an atomic number of 88
Czech:
rádium
— chemical element with an atomic number of 88
Dutch:
radium
— chemical element with an atomic number of 88
Esperanto:
radiumo
— chemical element with an atomic number of 88
Estonian:
raadium
— chemical element with an atomic number of 88
Finnish:
radium
— chemical element with an atomic number of 88
French:
radium
— chemical element with an atomic number of 88
Galician:
radio
— chemical element with an atomic number of 88
Georgian:
რადიუმი
(radiumi)
— chemical element with an atomic number of 88
German:
Radium
— chemical element with an atomic number of 88
Greek:
ράδιο
(rádio)
— chemical element with an atomic number of 88
Hebrew:
רדיום
(radiyum)
— chemical element with an atomic number of 88
Hindi:
तेजातु
(tejātu)
— chemical element with an atomic number of 88
Hindi:
रेडियम
(reḍiyam)
— chemical element with an atomic number of 88
Hungarian:
rádium
— chemical element with an atomic number of 88
Italian:
radio
— chemical element with an atomic number of 88
Japanese:
ラジウム
(rajiumu)
— chemical element with an atomic number of 88
Japanese:
ラディウム
(radiumu)
— chemical element with an atomic number of 88
Khmer:
រ៉ាដ្យូម
(raadyoum)
— chemical element with an atomic number of 88
Korean:
라듐
(radyum)
— chemical element with an atomic number of 88
Latvian:
rādijs
— chemical element with an atomic number of 88
Lithuanian:
radis
— chemical element with an atomic number of 88
Māori:
konuruke
— chemical element with an atomic number of 88
Norwegian Bokmål:
radium
— chemical element with an atomic number of 88
Norwegian Nynorsk:
radium
— chemical element with an atomic number of 88
Occitan:
radi
— chemical element with an atomic number of 88
Persian:
رادیوم
(râdiyom)
— chemical element with an atomic number of 88
Polish:
rad
— chemical element with an atomic number of 88
Portuguese:
rádio
— chemical element with an atomic number of 88
Romanian:
radiu
— chemical element with an atomic number of 88
Russian:
ра́дий
(rádij)
— chemical element with an atomic number of 88
Serbo-Croatian:
ра̑дӣј
— chemical element with an atomic number of 88
Serbo-Croatian:
rȃdīj
— chemical element with an atomic number of 88
Spanish:
radio
— chemical element with an atomic number of 88
Spanish:
radium
— chemical element with an atomic number of 88
Spanish:
rádium
— chemical element with an atomic number of 88
Swedish:
radium
— chemical element with an atomic number of 88
Tamil:
கருகன்
(karukaṉ)
— chemical element with an atomic number of 88
Thai:
เรเดียม
(ree-dîiam)
— chemical element with an atomic number of 88
Turkish:
radyum
— chemical element with an atomic number of 88
Ukrainian:
ра́дій
(rádij)
— chemical element with an atomic number of 88
Uyghur:
رادىي
(radiy)
— chemical element with an atomic number of 88
Uzbek:
radiy
— chemical element with an atomic number of 88
Vietnamese:
rađi
— chemical element with an atomic number of 88
Volapük:
radin
— chemical element with an atomic number of 88