Learner's definition of EXPEDITION
1 : a journey especially by a group of people for a specific purpose (such as to explore a distant place or to do research) — also used in a playful way to refer to a short trip for a specific purpose
◊ The phrase fishing expedition is sometimes used in a disapproving way, especially in U.S. English, to describe a situation in which a person or group looks for evidence that someone has done something wrong without having a good reason to believe the evidence exists.
a shopping expedition
2 : a group of people who travel together to a distant place : a group of people who go on an expedition