Etymology The adjective is first attested in 1825, the verb in 1658. Borrowed from Latin decussātus, perfect passive participle of decussō (“to divide crosswise, arrange crosswise or mark with a cross”) (see -ate (adjective-forming suffix) and -ate (verb-forming suffix)), from decussis (“a coin worth ten asses; a cross sign (from the cross shape of the Roman numeral for ten carved on the coins)”), from decem (“ten”) + as (“a Roman coin”).
1
Crossed; intersected; resembling a letter X.
2
Biology, Natural sciences, Zoology Having anatomical structures or markings crossing each other, typically in an X shape or at right angles.
3
Biology, Botany, Natural sciences Having opposite leaves arranged alternately at right angles.
Juniperites, ju-ne-per-i′tis, s[ubstantive]. A genus of fossil plants, in which the branches are ranged irregularly; leaves short, obtuse, inserted by a broad base, opposite, decussate, and arranged in four rows.1849, John Craig, “Juniperites”, in A New Universal Etymological, Technological, and Pronouncing Dictionary of the English Language, Embracing All the Terms Used in Art, Science, and Literature, volumes II (Jac–Zyt), London: Published (for the proprietors,) by Henry George Collins, 22 Paternoster Row, →OCLC, page 15:
4
Rhetoric Consisting of two rising and two falling clauses, placed in alternate opposition to each other.
Etymology The adjective is first attested in 1825, the verb in 1658. Borrowed from Latin decussātus, perfect passive participle of decussō (“to divide crosswise, arrange crosswise or mark with a cross”) (see -ate (adjective-forming suffix) and -ate (verb-forming suffix)), from decussis (“a coin worth ten asses; a cross sign (from the cross shape of the Roman numeral for ten carved on the coins)”), from decem (“ten”) + as (“a Roman coin”).
1
To form an X or to cross or intersect.
The two trochlears decussate in the anterior medullary velum.1949, Herbert Eugene Walter, Leonard Perkins Sayles, Biology of the Vertebrates: