noun · 3 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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lăn'thənəm
/ˈlænθənəm/
US:Recorded audio is listed in the source snapshot.
General-American:Recorded audio is listed in the source snapshot.
CMU ARPABET:L AE1 N TH AH0 N AH0 M
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
noun
Meaning 1
A chemical element (symbol La) with an atomic number of 57: a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air.
Definition source: English Wiktionary via Wiktextract
Usage: uncountable
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
2
noun
Meaning 2
An atom of this element.
Definition source: English Wiktionary via Wiktextract
Usage: countable
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
3
noun
Meaning 3
a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: La, atomic number 57
Antonyms: none provided
Broader terms: metallic element, metal
History
Etymology
From Ancient Greek λανθάνω (lanthánō, “to escape notice”) + -um (“a chemical element”), because it had gone long undetected in mineral ores.
Across languages
Translations
77 source translations are retained for this English entry.
Afrikaans:
lantaan
— metallic element
Albanian:
lantan
— metallic element
Arabic:
لَانْثَانُوم
(lānṯānūm)
— metallic element
Arabic:
لَانْتَانُوم
(lāntānūm)
— metallic element