Lewis & Short

2. intercursus, ūs, m. [intercurro], only abl. sing., a running between, intervention, interposition (rare, except in Liv.): periculum intercursu tum primum pubescentis filii propulsatum, Liv. 21, 46, 7: impeditus intercursu suorum, id. 37, 42, 4: consulum intercursu rixa sedata est, id. 2, 29, 4.
Of flashes of lightning: nox terribilis intercursu luminis diri, Sen. Q. N. 3, 27, 10.