alder

¹ American  

[awl-der] / ˈɔl dər /

noun

1. any shrub or tree belonging to the genus Alnus, of the birch family, growing in moist places in northern temperate or colder regions and having toothed, simple leaves and flowers in catkins.

2. any of various trees or shrubs resembling an alder.

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Alder ² American  

[ahl-der, ahl-duhr] / ˌɑl dər, ˈɑl dər /

noun

1. Kurt 1902–58, German chemist: Nobel Prize 1950.

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alder British  

/ ˈɔːldə /

noun

1. any N temperate betulaceous shrub or tree of the genus Alnus, having toothed leaves and conelike fruits. The bark is used in dyeing and tanning and the wood for bridges, etc because it resists underwater rot

2. any of several similar trees or shrubs

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Etymology

Origin of alder

before 900; Middle English alder, aller, Old English alor, al ( e ) r; cognate with Old Norse ǫlr, Middle Low German al ( l ) er < Germanic *álusṓ; akin to Middle High German alze < Germanic *alū́sō, Old High German elira, erila ( German Erle ) < Germanic *álisṓ, Middle Low German els ( e ) < Germanic *alísō, hence Germanic *álus, alísō; compare Polish olcha, Russian olʾkhá < Indo-European dialect *alisā; Lithuanian al̃ksnis, Latin alnus < Indo-European dialect *alsnos

Example Sentences

It looked at three trees common in Europe - birch, alder and olive - and found pollination started one to two weeks earlier between 2015 and 2024, compared with 1991 to 2000.

From BBC • Apr. 22, 2026

They look for hardy alder trees, which indicate an area that had been dug up for mining years ago.

From The Wall Street Journal • Nov. 8, 2025

The spacious kitchen is also accented with rich hardwood flooring, stone design elements, solid alder doors, and dual-pane windows.

From MarketWatch • Oct. 15, 2025

Pine, birch and eucalyptus reduced the virus' infectivity after four hours, and alder showed no antiviral effect.

From Science Daily • Jun. 19, 2024

Then they motored onward, up a rocky creek bed and through dense alder thickets.

From "Into the Wild" by Jon Krakauer