Definition of excurse:
(n) :
Synonym of excursus.
(v) :
(intransitive, now chiefly archaic and somewhat rare) To make a journey, especially an excursion; to travel.
(v) :
(intransitive, now rare) To digress; to turn aside from the main subject of attention.
(v) :
(transitive, obsolete) To travel or pass through.
(n) :
(obsolete) An act of moving or rushing forward or out; an incursion by troops.