Dunbar's Number
Noun · Hacker Culture
Definitions
The theoretical cognitive limit (~150) on the number of stable social relationships a human can maintain. In tech organizations, explains why communication breaks down above ~150 people and why companies need formal processes, documentation, and team boundaries beyond that size. The point where a startup stops feeling like a family.
In plain English: The idea that humans can only maintain about 150 meaningful relationships — companies above this size need more formal structure.
Example: "We hit 150 engineers and suddenly nobody knows what other teams are building — that's Dunbar's number. Time for better internal documentation."