Thulium

Part of speech: noun

Definitions

1. A rare chemical element with the symbol 'Tm' that is classified as a lanthanide and is used in certain types of materials and technologies
2. This metallic element is found in the periodic table as 'Tm', notable for its applications in areas such as lasers and medical imaging
3. An element in the group of lanthanides, identified by the symbol 'Tm', that has unique properties useful in scientific research and industrial applications

Etymology: Thulium takes its name from Thule, the ancient name for a remote land at the northern edge of the known world, which was later applied to Scandinavia. The element was named by Swedish chemist Per Teodor Cleve, who isolated it from minerals found near Ytterby, a village in Sweden that also gave names to several other rare earth elements. The "-ium" ending is the standard suffix chemists attached to newly discovered metals, drawn from the Latin "-ium" that marks many neuter nouns. Element names built this way follow a convention of naming a new metal after a place or source, so "thulium" joins a family of elements named in a similar manner. Thulium is a soft, silvery metal, and its name carries a distant geographic echo rather than any description of its properties. Its rarity in nature is reflected in how long it took chemists to isolate it in pure form.