rachis

noun

ra·​chis ˈrā-kəs How to pronounce rachis (audio) ˈra- How to pronounce rachis (audio)
plural rachises also rachides ˈra-kə-ˌdēz How to pronounce rachis (audio)
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
: spinal column

Examples of rachis in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
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

Word History

Etymology

New Latin rachid-, rachis, from Greek rhachis; akin to Greek rhachos thorn, Lithuanian ražas dry twig, tine

First Known Use

1785, in the meaning defined at sense 1

Time Traveler
The first known use of rachis was in 1785

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Cite this Entry

“Rachis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rachis. Accessed 10 Mar. 2025.

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