sodium

Sodium is a chemical element with atomic number 11 and the symbol Na. It is a soft, silvery-white, alkali metal that is highly reactive. It’s the sixth most abundant element in the earth’s crust. Sodium has myriad uses, perhaps most familiarly in the form sodium chloride or table salt.

The name sodium comes from soda, a post-classical Latin term for a headache, and sodanum, sodium carbonate, was sometimes used to treat headaches. These Latin words appear in the sixteenth century and are borrowings of the Arabic صُدَاع (ṣudāʿ). We see soda, in the sense of headache, appearing in English in a medical text by physician Andrew Boorde from c. 1540:

And contraryly, immoderate slepe and sluggyshnes doth humecte and maketh lyght the brayne; it doth ingendre rewme and impostumes; it is euyll for the palsy, whyther it be vnyuersall or partyculer; it is euyll for the fallynge syckenes called Epilencia, Analencia, & Cathalencia, Appoplesia, Soda, with all other infyrmytyes in the heade; for it induceth and causeth oblyuyousnes; for it doth obsuske and doth obnebulate the memorye and the quyckenes of wyt.

Chemist Humphry Davy was the first to isolate sodium and identify it as an element. He did so alongside potassium in 1807. It was Davy who dubbed the element sodium:

On this idea, in naming the bases of potash and soda, it will be proper to adopt the termination which, by common consent, has been applied to other newly discovered metals, and which, though originally Latin, is now naturalized in our language.

Potasium and Sodium are the names by which I have ventured to call the two new substances: and whatever changes of theory, with regard to the composition of bodies, may hereafter take place, these terms can scarcely express an error; for they may be considered as implying simply the metals produced from potash and soda.

The symbol Na comes from the post-classical Latin natrium, meaning soda ash or sodium carbonate, is a variant of the classical Latin nitrum, which comes from the Greek νίτρον (nitron), which in turn probably comes from Egyptian, perhaps borrowed into Greek via a Semitic language. Egypt was a major source of soda ash in the ancient world, and it was used in purification and mummification rituals. The Old Egyptian ntrj means sacred or divine.

Sources:

Boorde, Andrew. “A Compendyous Regyment or a Dyetary of Helth” (c. 1540). In The First Boke of the Introduction of Knowledge. F. J. Furnivall, ed. Early English Text Society, Extra Series 10. London: N. Trübner, 1870, 244. HathiTrust Digital Archive.

Davy, Humphry. “The Bakerian Lecture, on Some New Phenomena of Chemical Changes Produced by Electricity, Particularly the Decomposition of the Fixed Alkalies” (19 November 1807). Philosophical Transactions of the Royal Society of London, 98, 1808, 1–44 at 32. DOI: 10.1098/rstl.1808.0001.

Dictionary of Medieval Latin from British Sources, 2018, s.v. soda. Brepols: Database of Latin Dictionaries.

Glossarium mediae et infimae latinitatis (Du Cange), 1887, s.v. sodanum. Brepols: Database of Latin Dictionaries.

Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements: Part 2—Turbulent Nineteenth Century.” Foundations of Chemistry, 8 December 2022. DOI: 10.1007/s10698-022-09451-w.

Oxford English Dictionary, second edition, 1989, s.v. sodium, n., soda, n.1., soda, n.2; third edition, December 2003, nitre | nitre, n.

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