insider

Etymology

It was formed in English from inside and the agent suffix -er.^{[2][3][4][5][6]}

Earliest recorded meaning

A person within an organization or group, and so one who has special information: 1848, in W. Armstrong's Stocks,^[2][7][4] originally in reference to the stock markets.^[3] The Shorter Oxford dates an earlier sense, a passenger travelling inside a coach, to the early 19th century,^[5] and Dictionary.com dates the word to 1820–30.^[6]

Semantic evolution

The coach-passenger sense, recorded by the OED from 1854 to 1892, died out with stagecoach travel.^[2][5] In American thieves' slang an insider was a pocket or pocketbook, from 1846.^[2][7] The main sense, a member of a group with access to its secrets, kept its link with finance: an insider in American securities law is an officer or director of a company, or a large shareholder, whose trading in its shares is regulated.^[4] The compounds insider dealing and insider trading name the illegal use of such knowledge to trade shares.^[8][5] In Australian slang the word has meant a secret informant within an institution such as the police.^[9]

Timeline

• 1846 – (US slang) a pocket or pocketbook.^[2]
• 1848 – a member of a group, one with special information.^[2][4]
• 1854 – an inside passenger in a coach.^[2]

Modern meaning

Noun

1. A person who belongs to a group or organization, especially one with access to its confidential information: According to an industry insider, the merger will be announced next week.
2. (finance) An officer, director or major shareholder of a company, whose dealings in its shares are restricted by law.
3. (historical) A passenger who travelled inside a coach.

Word family

• insider trading

Related words

• inside
• outsider

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b 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 c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
7. ^ a b Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
8. ^ Jones, Daniel (2011), Cambridge English Pronouncing Dictionary, 18th ed., ed. Peter Roach, Jane Setter and John Esling, Cambridge: Cambridge University Press
9. ^ Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com