Expedition, n.
Etymology: [L. expeditio: cf.F. expédition.]
1. The quality of being expedite; efficient promptness; haste; dispatch; speed; quickness; as to carry the mail with expedition. With winged expedition Swift as the lightning glance.
2. A sending forth or setting forth the execution of some object of consequence; progress. Putting it straight in expedition.
3. An important enterprise, implying a change of place; especially, a warlike enterprise; a march or a voyage with martial intentions; an excursion by a body of persons for a valuable end; as, a military, naval, exploring, or scientific expedition; also, the body of persons making such excursion. The expedition miserably failed. Prescott. Narrative of the exploring expedition to the Rocky Mountains. J. C. Fremont.
Shades of meaning
Fernald has no entry of its own for expedition; he lists it under journey.
He lists it without comment; the entries above explain its neighbors.