Definition of decussate in US English:



[no object]technical
  • (of two or more things) cross or intersect each other to form an X.

    ‘the fibers decussate in the collar’
    • ‘The central canal and surrounding gray matter appear as though pushed dorsally by the decussating bundles of axons.’
    • ‘These decussating bundles can be seen distinctly between the lips of the ventral median fissure.’
    • ‘After decussating, these fibers ascend in a compact, ribbon like tract called the medial lemniscus.’
    cross, criss-cross
    View synonyms


  • 1Shaped like an X.

    1. 1.1Botany (of leaves) arranged in opposite pairs, each pair being at right angles to the pair below.
      • ‘This is much simpler than those reproductive organs of living Gnetales with a cone-like inflorescence that is organized by paired or decussate bracts.’
      • ‘Orchids, however, have all possible tetrad types: linear, decussate, square, tetrahedral, rhomboid and T-shaped are all reported.’
      • ‘This plant resembles some trimerophytes, such as Pertica, in that it has three-dimensional branching with branches arranged in a spiral or decussate pattern.’
      • ‘For example, many pioneer trees exhibit orthotropic (vertically oriented) shoots that successively produce leaves in spiral or decussate phyllotaxy.’


Mid 17th century (as a verb): from Latin decussatus, past participle of decussare ‘divide crosswise’, from decussis (describing the figure X, i.e. the Roman numeral for the number 10), from decem ‘ten’.