Definition of lanthanum in English:

lanthanum

noun

  • The chemical element of atomic number 57, a silvery-white rare earth metal.

    • ‘Green light is also emitted from some lanthanide elements: lanthanum, cerium, and terbium.’
    • ‘Its chemical properties are similar to those of lanthanum, the element above it in the periodic table.’
    • ‘It belongs to the family known as the lanthanides, named after the first member of that series, lanthanum.’
    • ‘Samarium is a rare earth element, one of the elements that occupy the space in Row 6 of the periodic table between lanthanum and hafnium.’
    • ‘Oxalate efflux could not be triggered by treatment with the trivalent cation lanthanum or by phosphorus deficiency, indicating that the efflux was specific to the Al treatment.’

Origin

Mid 19th century: from Greek lanthanein escape notice (because it was long undetected in cerium oxide) + -um.

Pronunciation:

lanthanum

/ˈlanTHənəm/