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- Dictionaryrachis/ˈreɪkɪs/
noun
- 1. a stem of a plant, especially a grass, bearing flower stalks at short intervals.
- 2. the vertebral column or the cord from which it develops.
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: 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.
In plants, a rachis is the main axis of a compound structure. It can be the main stem of a compound leaf, such as in Acacia or ferns, or the main, flower-bearing portion of an inflorescence above a supporting peduncle. Where it subdivides into further branches, these are known as rachillae (singular rachilla).
Rachis definition: the axis of an inflorescence when somewhat elongated, as in a raceme.. See examples of RACHIS used in a sentence.
one of a pair of crescent-shaped cells that surround a pore (stoma) in the epidermis. Changes in the turgidity of the cells cause the opening and closing of the stoma. xylem root guard cell.
1. any of various axial structures of a plant, as the stem of a leaflet. 2. the part of the shaft of a feather bearing the web.
1. a thornlike process or projection; called also acantha and spina. 2. the rigid bony structure in the midline of the back, composed of the vertebrae; called also backbone, spinal column, and vertebral column. The spinal column is the axis of the skeleton; the skull and limbs are in a sense appendages.
Definitions of rachis. noun. axis of a compound leaf or compound inflorescence. see more. noun. the series of vertebrae forming the axis of the skeleton and protecting the spinal cord. synonyms: back, backbone, spinal column, spine, vertebral column. see more.
