noun, plural rha·chis·es, rhach·i·des [rak-i-deez, rey-ki-] /ˈræk ɪˌdiz, ˈreɪ kɪ-/.
noun, plural ra·chis·es, rach·i·des [rak-i-deez, rey-ki-] /ˈræk ɪˌdiz, ˈreɪ kɪ-/.
- 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.
Origin of rachis
1775–85; < New Latin < Greek rháchis spine, ridge, backboneRelated 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
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
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British Dictionary definitions for rhachis
noun plural rhachises or rhachides (ˈrækɪˌdiːz, ˈreɪ-)
noun plural rachises, rhachises, rachides or rhachides (ˈrækɪˌdiːz, ˈreɪ-)
Derived Formsrachial or rhachial (ˈreɪkɪəl) or rachidial or rhachidial (rəˈkɪdɪəl), adjective
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
Word Origin for rachis
C17: via New Latin from Greek rhakhis ridge
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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The American Heritage® Stedman's Medical Dictionary
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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
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