The story
Introduced by Christos Papadimitriou and Mihalis Yannakakis in 1989. Supposed to allude to the difficulties experienced by Canadian drivers with snowfall randomly blocking roads.
Etymology from Wiktionary, CC BY-SA 4.0.
Canadian traveller problem
Today it means: A generalization of the shortest path problem to graphs that are only partially observable (i.e. the graph is revealed while it is being explored). Full definition →