plural rachises also rachides
ˈra-kə-ˌdēz 
ˈrā-
1
: an axial structure: such as
a(1)
: the elongated axis of an inflorescence
(2)
: an extension of the petiole of a compound leaf that bears the leaflets
b
: the distal part of the shaft of a feather that bears the web
2
Examples of rachis in a Sentence
Recent Examples on the Web
Reinforcements in the bones of the hummingbird wing provide some of this rigidity; feathers with extremely firm rachises provide the rest.
—
Michael B. Habib, Scientific American, 16 Apr. 2024
The bristle feathers that typically occur on the face and may serve protective and sensory purposes meld the flight feathers’ stiff shafts (called rachises) with the down feathers’ fluffy base.
—Michael B. Habib, Scientific American, 16 Apr. 2024
The primary feathers on older woodcock are also less symmetrical than those on younger birds, with one wider edge on the outside of the rachis, or centerline.
—Matthew Every, Field & Stream, 18 Oct. 2023
Like those of modern birds, these feathers had two asymmetrical vanes coming off a central shaft or ‘rachis’.
—Ed Yong, Discover Magazine, 13 May 2010
It is sometimes referred to as the rachis.
—Rita Perwich, San Diego Union-Tribune, 5 Feb. 2022
There are also barbules that branch off directly from the rachis, in between points where the barbs branch off.
—Gemma Tarlach, Discover Magazine, 8 Dec. 2016
From its main shaft, called the rachis, thousands of filaments called barbs branched off.
—Carl Zimmer, Discover Magazine, 18 Jan. 2011
In stage three, the barbs partially unite to form a central rachis, and even smaller filaments called barbules start to branch off from the barbs.
—Discover Magazine, 12 Sep. 2011
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Michael B. Habib, Scientific American, 16 Apr. 2024
The bristle feathers that typically occur on the face and may serve protective and sensory purposes meld the flight feathers’ stiff shafts (called rachises) with the down feathers’ fluffy base.
—Michael B. Habib, Scientific American, 16 Apr. 2024
The primary feathers on older woodcock are also less symmetrical than those on younger birds, with one wider edge on the outside of the rachis, or centerline.
—Matthew Every, Field & Stream, 18 Oct. 2023
Like those of modern birds, these feathers had two asymmetrical vanes coming off a central shaft or ‘rachis’.
—Ed Yong, Discover Magazine, 13 May 2010
It is sometimes referred to as the rachis.
—Rita Perwich, San Diego Union-Tribune, 5 Feb. 2022
There are also barbules that branch off directly from the rachis, in between points where the barbs branch off.
—Gemma Tarlach, Discover Magazine, 8 Dec. 2016
From its main shaft, called the rachis, thousands of filaments called barbs branched off.
—Carl Zimmer, Discover Magazine, 18 Jan. 2011
In stage three, the barbs partially unite to form a central rachis, and even smaller filaments called barbules start to branch off from the barbs.
—Discover Magazine, 12 Sep. 2011
Dictionary Entries Near rachis
Cite this Entry
“Rachis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rachis. Accessed 26 Nov. 2024.
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