\De*cus"sate\, v. t. [imp. & p. p. {Decussated}; p.
pr. & vb. n. {Decussating}.] [L. decussatus, p. p. of
decussare to cross like an X, fr. decussis (orig. equiv. to
decem asses) the number ten, which the Romans represented by
X.]
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.

\De*cus"sate\, Decussated \De*cus"sa*ted\, a.
1. Crossed; intersected.
2. (Bot.) Growing in pairs, each of which is at right angles
   to the next pair above or below; as, decussated leaves or
   branches.
3. (Rhet.) Consisting of two rising and two falling clauses,
   placed in alternate opposition to each other; as, a
   decussated period.