oak
Americannoun
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any tree or shrub belonging to the genus Quercus, of the beech family, bearing the acorn as fruit.
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the hard, durable wood of an oak tree, used in making furniture and in construction.
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Archaic. the leaves of an oak tree, especially as worn in a chaplet.
adjective
idioms
noun
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any deciduous or evergreen tree or shrub of the fagaceous genus Quercus, having acorns as fruits and lobed leaves See also holm oak cork oak red oak Turkey oak durmast
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the wood of any of these trees, used esp as building timber and for making furniture
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( as modifier )
an oak table
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any of various trees that resemble the oak, such as the poison oak, silky oak, and Jerusalem oak
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anything made of oak, esp a heavy outer door to a set of rooms in an Oxford or Cambridge college
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to shut this door as a sign one does not want visitors
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the leaves of an oak tree, worn as a garland
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the dark brownish colour of oak wood
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any of various species of casuarina, such as desert oak, swamp oak, or she-oak
Other Word Forms
Etymology
Origin of oak
First recorded before 900; Middle English ok(e), oc, Old English āc; cognate with Dutch eik, German Eiche, Old Icelandic eik; further origin uncertain
Explanation
An oak is a tree that typically sheds its leaves in the winter and grows acorns as fruit. If you get hit on the head with an acorn, you are probably standing under an oak. There are many species of oaks, a few of which are evergreen, keeping their leaves all year, but most have bright leaves in the fall and are bare for the winter months. An oak table or oak desk is made from the sturdy wood of an oak tree. The strength of oaks has inspired several countries to adopt them as symbols on money and flags, and in 2004 the oak was voted the national tree by the US Congress.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The guest pass can be applied for online the day of or up to seven days in advance of visiting OAK.
From Los Angeles Times • Dec. 18, 2025
When TSA approves an application, the visitor will get an approval email that includes an attachment of their electronic OAK Guest Pass.
From Los Angeles Times • Dec. 18, 2025
The airport’s three-letter code, OAK, will remain the same, much to the relief of travel agents and airline ticketing systems.
From Los Angeles Times • May 10, 2024
The airport’s three-letter code OAK would not change.
From Seattle Times • Apr. 10, 2024
THE OAK Yes, I know that you are looking for the Blue Bird, that is to say, the great secret of things and of happiness, so that Man may make our servitude still harder….
From The Blue Bird: a Fairy Play in Six Acts by Teixeira de Mattos, Alexander
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
