ligand

Etymology

It is borrowed from Latin ligandus (“that is to be bound”), the gerundive of ligō (“to bind, tie”),^{[2][3][4][5][6][7]} from Proto-Indo-European *leig- (“to tie, bind”).^[3] Collins gives the gerund ligandum instead.^[8] The same verb is the source of ligate and ligature.^[5][4][3]

Earliest recorded meaning

An atom or group attached to the central atom of a co-ordination complex: 1938, in the Bulletin of the Chemical Society of Japan.^[2] Merriam-Webster Unabridged dates the word to 1949, Dictionary.com to 1945–50, and Etymonline to 1952.^[4][9][3]

Semantic evolution

The word was coined in coordination chemistry, for the molecules, ions or atoms bonded to a central, usually metal, atom;^[2][7] the related term ligand field names the electrostatic field these produce around the central atom.^[7] From 1968 it was taken up in immunology and biochemistry for any molecule that binds specifically to another, usually a large molecule,^[2] as a substance binding to a receptor.^[10]

Timeline

• 1938 – an atom or group bound to the central atom of a co-ordination complex.^[2]
• 1968 – in immunology, a molecule that binds specifically to another, usually larger molecule.^[2]

Meanings

Noun

1. (chemistry) An ion, molecule or group bonded to the central atom of a coordination complex.^[4][8][2]
2. (biochemistry) A molecule that binds specifically to another, usually a macromolecule such as a receptor.^[2][10]

Related words

• ligate
• ligature
• ligament
• oblige
• liable

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins
9. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
10. ^ a b Stedman's Medical Dictionary, Baltimore: Lippincott Williams & Wilkins