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 (?), 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.