What is defined as a journey made for a special purpose?

An expedition is defined as a journey made for a special purpose, often involving exploration, scientific research, or a significant mission. These journeys typically have well-defined goals and objectives, such as exploring uncharted territories or conducting research in areas that require specialized skills and equipment. Expeditions are usually organized and can involve a group of people working toward a common purpose, such as discovering new regions or studying specific phenomena.

In contrast, a voyage generally refers to a long journey by sea or in space, which may not necessarily have a specific purpose beyond travel itself. An excursion, on the other hand, is usually a short journey taken for leisure or educational purposes, without the overarching goal or significant intent that characterizes an expedition. A quest implies a search or pursuit towards a particular goal, often with a sense of adventure or urgency, but it does not specifically signify a journey, making expedition the most fitting term for a special-purpose journey.