- 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
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for rhachis
The lower valve of the calyx turned to the rhachis is more than twice as small as the upper.
Rhachis hairy at the base of the flowers, ending in a naked pedicel.
Spikelets 3–12-flowered, somewhat terete, the rhachis with bearded joints; terminal flower abortive.
- a variant spelling of rachis
- 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
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
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- 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.