Decussate \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. Decussate