airtight

Etymology

It is formed from English air + tight,^[2][3][4] after the earlier watertight.^[2]

Earliest recorded meaning

Impermeable to air: 1728, in the Philosophical Transactions of the Royal Society.^[2][5] Etymonline and Merriam-Webster's Collegiate date the word to 1760,^[3][6] and Dictionary.com to 1750–60.^[4]

Semantic evolution

The literal sense, impermeable to air, also gave a figurative one, closed off or impenetrable.^[2] An adverb, so as to keep air out, is recorded from 1777.^[2] In American English the word came to mean "that cannot be faulted, incontrovertible", first of a sure thing in betting: Green's Dictionary of Slang has it from 1896,^[7] the OED from 1901, in George Ade,^[2] and Etymonline only from 1929, of arguments and alibis.^[3] American slang also used it for "very attractive" in a flapper glossary of 1922,^[7] and in underworld speech for a town where the authorities had been paid off and criminals were safe.^[7] As a noun, an airtight was an airtight stove from 1844, a use the Dictionary of American Regional English calls chiefly northeastern and obsolescent;^[2][8] from 1897 it also meant food preserved in an airtight can.^[2]

Timeline

• 1728 – impermeable to air.^[2][5]
• 1777 – adverb, so as to keep out air.^[2]
• 1844 – noun, an airtight stove.^[2][8]
• 1896 – sure, guaranteed; later, incontrovertible.^[7][2]
• 1897 – noun, food preserved in an airtight can.^[2]
• 1922 – in slang, very attractive.^[7]

Meanings

Adjective

1. So tightly sealed that no air can pass in or out: Keep the rice in an airtight jar.^[9][5][2]
2. Having no weak point, flaw or loophole; unassailable: an airtight case against the suspect.^[9][5][2]
3. Allowing an opponent no chance to score: an airtight defence.^[5][6]

Adverb

1. So as to be impermeable to air.^[2]

Noun

1. A stove that admits very little air.^[2][8]
2. Food preserved in an airtight container, especially a can.^[2]

Word family

• airtightness
• airtightly

Related words

• air
• tight
• watertight

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 q r Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
5. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
6. ^ a b Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
7. ^ a b c d e Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com
8. ^ a b c Cassidy, Frederic G. & Joan Houston Hall (eds.) (1985–2002), Dictionary of American Regional English, vols I–IV, Cambridge, Mass.: Belknap Press of Harvard University Press
9. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins