terminator

Etymology

It is partly borrowed from Late Latin terminātor (“one who sets bounds”), and partly formed from English terminate + -or.^[2][3] In post-classical Latin the noun meant a person who fixes boundaries (in Augustine, of a god), and later the horizon and the line between the lit and dark parts of the moon or a planet.^[2] It is an agent noun from terminō (“to mark the end or boundary”), from terminus (“end, limit”).^[4][2][5] The OED compares French terminateur, used in astronomy from 1546 in Middle French,^[2] and Etymonline notes the earlier Middle English terminour (“inflectional ending of a word”) (about 1400), from a variant of Old French termineor.^[4][6]

Earliest recorded meaning

A person or thing that ends something: 1652, in J. Lane's Persecution Detected.^[2] The astronomical sense followed in 1661, in T. Salusbury's translation of Galileo.^[2]

Semantic evolution

The OED's earliest sense is the general one, someone or something that brings a thing to an end;^[2] the Shorter Oxford and Etymonline, which take the astronomical sense as the first, date the general use only to the mid 19th century (Etymonline, 1844).^[3][4] In astronomy the word names the line dividing the lit and unlit parts of the disc of the moon or a planet, borrowed from the post-classical Latin of Galileo's day;^[2][3] Etymonline dates it to 1734^[4] and Merriam-Webster to 1770.^[7] In later use the general sense was applied especially to an exterminator or a professional killer.^[2] Since 1965 molecular biology has used it for a sequence of nucleotides that signals the end of transcription or translation.^[2][3][8]

Timeline

• 1652 – a person or thing that ends something.^[2]
• 1661 – in astronomy, the line between the lit and dark parts of the moon or a planet.^[2] Etymonline dates this sense to 1734.^[4]
• 1965 – in molecular biology, a sequence of nucleotides that signals the end of transcription or translation.^[2]

Meanings

Noun

1. A person or thing that terminates something: She was the terminator of several costly projects.^[7][8][9]
2. In astronomy, the dividing line between the lit and the dark part of the disc of the moon or a planet.^{[7][8][10][2]}
3. In genetics and molecular biology, a codon or longer sequence of nucleotides that signals the end of transcription or translation.^[7][8][3][2]
4. An exterminator; a professional assassin.^[2]

Related words

• terminate
• termination
• terminus
• term
• exterminator
• determine

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
7. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ a b c d The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
9. ^ The Chambers Dictionary (2014), 13th ed., Edinburgh: Chambers
10. ^ Collins English Dictionary (2023), Glasgow: HarperCollins