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rhachis

[rey-kis]

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SEE MORE SYNONYMS FOR rhachis ON THESAURUS.COM

noun, plural rha·chis·es, rhach·i·des [rak-i-deez, rey-ki-] /ˈræk ɪˌdiz, ˈreɪ kɪ-/.

rachis

or rha·chis

[rey-kis]

noun, plural ra·chis·es, rach·i·des [rak-i-deez, rey-ki-] /ˈræk ɪˌdiz, ˈreɪ kɪ-/.

Botany.

the axis of an inflorescence when somewhat elongated, as in a raceme.
(in a pinnately compound leaf or frond) the prolongation of the petiole along which the leaflets are disposed.
any of various axial structures.

Ornithology. the part of the shaft of a feather bearing the web.

Anatomy. spinal column.

Origin of rachis

1775–85; < New Latin < Greek rháchis spine, ridge, backbone

Related formsra·chid·i·an

[ruh-kid-ee-uh n] /rəˈkɪd i ən/, ra·chi·al

[rey-kee-uh l] /ˈreɪ ki əl/, ra·chid·i·al, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for rhachis

backbone, spine, rachis, vertebrae

Examples from the Web for rhachis

Historical Examples of rhachis

The lower valve of the calyx turned to the rhachis is more than twice as small as the upper.
Travels in the Interior of North America, 1832-1834, Part III (the Text Being Chapters XXVIII-XXXIII of the London Edition, 1843, and the Appendix a Combination of the Appendices of the London and German [Coblentz, 1839] Editions)
Maximilian, Prinz von Wied
Rhachis hairy at the base of the flowers, ending in a naked pedicel.
The Manual of the Botany of the Northern United States
Asa Gray
Spikelets 3–12-flowered, somewhat terete, the rhachis with bearded joints; terminal flower abortive.
The Manual of the Botany of the Northern United States
Asa Gray

British Dictionary definitions for rhachis

rhachis

noun plural rhachises or rhachides (ˈrækɪˌdiːz, ˈreɪ-)

a variant spelling of rachis

rachis

rhachis

noun plural rachises, rhachises, rachides or rhachides (ˈrækɪˌdiːz, ˈreɪ-)

botany the main axis or stem of an inflorescence or compound leaf

ornithol the shaft of a feather, esp the part that carries the barbs

another name for spinal column

Derived Formsrachial or rhachial (ˈreɪkɪəl) or rachidial or rhachidial (rəˈkɪdɪəl), adjective

Word Origin for rachis

C17: via New Latin from Greek rhakhis ridge

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

rhachis in Medicine

rachis

[rā′kĭs]

n. pl. ra•chis•es

spinal column

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

rhachis in Science

rachis

[rā′kĭs]

Plural rachises rachides (răk′ĭ-dēz′, rā′kĭ-)

A main axis or shaft, such as the main stem of an inflorescence, the stalk of a pinnately compound leaf, the shaft of a feather, or the spinal column.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.