Decusso, decussas, decussâre. Colum. To cutte or diuide after the forme of the letter x, made crossewise: to cutte equally in the middes crossewise.
Lewis and Short: Latin dictionary
dĕcusso, āvi, ātum, 1, v. a. [decussis, no. I.], to divide crosswise, in the form of an X, to decussate, Cic. Univ. 7 med.; Col. 3, 13, 12; 4, 17, 6 al.