Coordination is the challenge of distinct actors being able to jointly choose their actions to achieve a favorable outcome. An example of easy coordination is coordinating to drive on the same side of the road. A hard example is coordinating everyone to move a superior yet different social media platform. Many failures of civilization are failures of coordination. A closely related concept is that of cooperation – multiple actors choosing their actions in ways that maximize collective value despite the temptation of greater short-term individual gain by acting to the detriment of the group/other actors. The Prisoner's Dilemma is the canonical cooperation/defection game, but the term is used in other games too, e.g. Stag Hunt.
Coordination and cooperation are fundamental concepts in Game Theory. LessWrong discussion has long been interested in overcoming the gnarly coordination and cooperation challenges that prevent many improvements to optimizing the world. There is also interest because failures to coordinate/cooperate are likely causes of existential risks such as AI Risk or nuclear war.
Another related term in this space is collective action problem.