Pronunciation: (ik-skûr'zhun, -shun),[key] —n. 1. a short trip or outing to some place, usually for a special purpose and with the intention of a prompt return: a pleasure excursion; a scientific excursion. 2. a trip on a train, ship, etc., at a reduced rate: weekend excursions to mountain resorts. 3. the group of persons making such a journey: an excursion of tourists. 4. a deviation or digression: excursions into futile philosophizing. 5. Physics.the displacement of a body or a point from a mean position or neutral value, as in an oscillation.
6. an accidental increase in the power level of a reactor, usually forcing its emergency shutdown.
7. Mach. a. the range of stroke of any moving part.
b. the stroke itself.
8. Obs.a sally or raid.
—v.i. to go on or take an excursion.
—adj. of, pertaining to, or intended for use on excursions: an excursion fare; an excursion bus.