Schelling point
Etymology
Named for the economist Thomas Schelling, who posed the puzzle in 1960: if you had to meet a stranger in New York with no way to communicate, where and when would you go? Enough people answer "Grand Central at noon" that it works. The focal point everyone guesses others will guess now bears his name.
noun · /SHEL-ing point/
A solution people tend to converge on without communicating, because it seems natural or obvious to everyone.
What it names
How strangers coordinate with no plan — where to meet in a city you don’t know, which line to form, what counts as "normal."
Example
With no agenda set, "let’s just meet at the entrance" became the Schelling point everyone assumed.
Related idea
A convention is a Schelling point that has hardened into a rule.