▪ I. decussate, a.
(dɪˈkʌsət)
[ad. L. decussāt-us, pa. pple. of decussāre: see decuss.]
1. Having the form of an X.
| 1825 Hone Every-day Bk. I. 1538 The letter X, styled a cross decussate. 1882 Farrar Early Chr. I. 85 The decussate cross now known as the cross of St. Andrew. |
2. Bot. Of leaves, etc.: Arranged on the stem in successive pairs, the directions of which cross each other at right angles, so that the alternate pairs are parallel.
| 1835 Lindley Introd. Bot. (1848) II. 382 Decussate, arranged in pairs that alternately cross each other. 1884 Bower & Scott De Bary's Phaner. 259 The stem has four angles, and bears decussate pairs of opposite leaves. |
Hence deˈcussately adv., in a decussate manner.
| 1846 Dana Zooph. (1848) 329 Folia..transversely coalescent or intersecting one another (decussately aggregated). |
▪ II. decussate, v.
(ˈdɛkəseɪt, dɪˈkʌseɪt)
[f. L. decussāt-, ppl. stem of decuss-āre: see decuss.]
1. trans. To cross, intersect, lie across, so as to form a figure like the letter X.
| 1658 Sir T. Browne Gard. Cyrus iii. 53 The right and transverse fibres are decussated by the oblick fibres. 1665–6 Phil. Trans. I. 221 These Rainbows did not..decussate one another at right angles. 1737 Bracken Farriery Impr. (1756) I. 58 The inner [fibres] always decussate or cross the outer. 1835–6 Todd Cycl. Anat. I. 583/1 Their medullary fibres..converge and decussate each other. |
2. intr. To cross or intersect each other; to form a figure like the letter X.
| 1713 Derham Phys. Theol. iv. vii. 153 The Fibres of the external and internal Intercostals decussate. 1835–6 Todd Cycl. Anat. I. 251/1 Sometimes they [ligaments] cross or decussate with each other. 1875 Blake Zool. 198 Optic nerves, commissurally united, not decussating. |