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rachis
[ rey-kis ]
noun
- 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.
rachis
/ ˈreɪkɪs; ˈreɪkɪəl; rəˈkɪdɪəl /
noun
- 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
rachis
/ ′ĭ /
, Plural rachises ă′ĭ-dēz′,′ĭ-
- 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.
Derived Forms
- rachial, adjective
Other 51Թs From
- ··· [r, uh, -, kid, -ee-, uh, n], ·· [rey, -kee-, uh, l], ·i· adjective
51Թ History and Origins
Origin of rachis1
51Թ History and Origins
Origin of rachis1
Example Sentences
“The thickness of the rachis in some specimens is 3 microns thick. That’s less than the size of the average cell,” O’Connor says.
It had a magenta rachis down the center with soft green vanes that shimmered yellow and purple and blue depending on how you turned it.
But this specimen lacked the rachis; it just had barbs and barbules down its ribbonlike tail.
Their structure suggests that the two finest tiers of branching in modern feathers, known as barbs and barbules, arose before the rachis formed.
Fruit.—Fleshy, coalescent and sunk in the rachis.
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