reactio

Forms

reāctiō f (genitive reāctiōnis); third declension^[1]

Etymology

It is from Latin reagō (“to act again; to react”) + -tiō.^[1] The DMLBS analyses it as re- (“back, again”) and āctiō (“action”),^[2] and Etymonline as a noun of action formed on the past-participle stem of the verb.^[3]

Earliest recorded meaning

Its first dated author is Thomas Bradwardine (1344), who says the air could cause a carbuncle's light only per viam reflexiōnis aut reactiōnis, “by way of reflection or reaction”.^[2][4] John Wyclif's Logic argues from the impossibility of a reaction of two elements on each other at the same time.^[2]

Semantic evolution

It was a word of scholastic natural philosophy, for the action of a thing in return on what acts on it.^[2][5] In New Latin it was used in physics and chemistry,^[1] and the modern words are borrowed from it: French réaction, Italian reazione, Spanish reacción, Dutch reactie and German Reaktion.^[1] Etymonline says English reaction, first recorded in the 1640s, was modelled on French and older Italian reattione after the Medieval Latin word, and was at first a term of physics and dynamics; the chemical sense is from 1836 and the general sense “response” from 1914.^[3]

Timeline

• 1344 – Thomas Bradwardine names reaction beside reflection.^[2][4]
• 1640s – English reaction is recorded.^[3]
• 1836 – English uses its word in chemistry.^[3]

Meanings

Noun

1. (Medieval Latin) Reaction, the action of a body in return on what acts on it.^[2][5][1]
2. (New Latin, physics, chemistry) A physical or chemical reaction.^[1]

Related words

• āctiō
• English reaction

References

1. ^ a b c d e f g h Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f Latham, R. E., D. R. Howlett, R. K. Ashdowne, et al. (1975–2013), Dictionary of Medieval Latin from British Sources, London: British Academy / Oxford University Press
3. ^ a b c d Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
5. ^ a b Stelten, Leo F. (1995), Dictionary of Ecclesiastical Latin, Peabody, Mass.: Hendrickson