diatom

Noun (1)

diatom (plural diatoms)

1. Any of a group of minute unicellular algae having a siliceous covering of great delicacy, now categorized as class Diatomophyceae or division Bacillariophyta.
   • Diatoms are enclosed in two shells that fit together like a pillbox.1967, George K. Reid, edited by Herbert S. Zim and George S. Fichter, Pond Life, New York: Golden Press, →LCCN, →OCLC, page 31
   • Diatoms are characterized by a cell wall called a fistula made of silica, which usually has two overlapping sections.2012, Caspar Henderson, The Book of Barely Imagined Beings, Granta Books, published 2013, page 287

Noun (2)

UK/daɪˈæ.təm/US/daɪˈæ.təm/

diatom (plural diatoms)

1. A molecule composed of two atoms of the same element; a homonuclear diatomic molecule.
   • We show here, through a systematic study of the covalent chemical bond covering the entire periodic system, that the maximum bond multiplicity is six. The maximum value is reached by the tungsten diatom, W₂. No other pair of atoms in the periodic system (atomic numbers smaller than about 100)...2007, Björn O. Roos, Antonio C. Borin, Laura Gagliardi, “Reaching the Maximum Multiplicity of the Covalent Chemical Bond”, in Angewandte Chemie, volume 46, number 9, →DOI, archived from the original...