from The American Heritage® Dictionary of the English Language, 4th Edition

  • transitive v. To cross or become crossed so as to form an X; intersect.
  • adj. Intersected or crossed in the form of an X.
  • adj. Botany Arranged on a stem in opposite pairs at right angles to those above or below, resulting in four vertical rows: decussate leaves.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Crossed; intersected; resembling a letter X.
  • adj. Having opposite leaves arranged alternately at right angles.
  • adj. Consisting of two rising and two falling clauses, placed in alternate opposition to each other.
  • v. To form an X or to cross or intersect.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Crossed; intersected.
  • adj. Growing in pairs, each of which is at right angles to the next pair above or below.
  • adj. Consisting of two rising and two falling clauses, placed in alternate opposition to each other.
  • transitive v. To cross at an acute angle; to cut or divide in the form of X; to intersect; -- said of lines in geometrical figures, rays of light, nerves, etc.

from The Century Dictionary and Cyclopedia

  • To intersect; cross, as lines, rays of light, leaves, or fibers of nerves.
  • Crossed; intersected: specifically applied, in bot, to bodies which are arranged in pairs alternately crossing each other at regular angles.
  • In rhetoric, arranged in two pairs of repeated, contrasted, or parallelized words or phrases, the second pair reversing the order of the first; characterized by or constituting such an arrangement; chiastic. See chiasmus.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • v. cross or intersect so as to form a cross
  • adj. crossed or intersected in the form of an X


Latin decussāre, decussāt-, from decussis, the number ten, intersection of two lines (from the Romans' use of X for the numeral 10), a ten-as coin : decem, ten; see dekm̥ in Indo-European roots + assis, as (coin).
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin decusso ("arrange crosswise or mark with a cross"), from decussis ("a 10 asses coin"), from decem ("ten") + as ("a Roman coin"). Based on the cross marking on the decussis coin. (Wiktionary)



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  • "The unmarked, decussating paths would have been confusing to anyone but a native."
    The Diamond Age by Neal Stephenson, p 375 of the Spectra trade paperback

    May 25, 2016

  • Not as messy, anyway, c_b.

    May 27, 2009

  • An odd formation. I wonder where the [u] came from in decem-ass-. Assuming it was formed after m was replaced by vowel nasalization (decem 'deke~:), I would have thought you'd expect decess-. I see from Perseus that all the compounds from seven have the 'wrong' vowel, so it might be levelling by analogy with neighbouring numbers.

    May 27, 2009

  • ... I guess it was better to carry around a copper coin than ten actual asses.

    May 27, 2009

  • The word originated from Latin "as" (plural asses) which was a copper coin and the monetary unit in ancient Rome. The word for ten asses was decussis, from Latin decem (ten) + as (coin). Since ten is represented by X, this spawned the verb decussare, meaning to divide in the form of an X or intersect.

    May 27, 2009