Definição
Tribal knowledge is an informal industry term for know-how held collectively by a group of experienced employees and never formally written down: the undocumented fixes, tolerances, exceptions and judgment calls that make a process work in practice rather than on paper. In business, manufacturing and software it almost always signals a documentation gap rather than a shortage of expertise.
Porque importa
Undocumented knowledge is a single point of failure that no risk register records. Work proceeds normally until the one person who knows the exception is on leave, changes team or retires, at which point a process that looked robust turns out to have been held together by memory. Note on the term itself: many organizations and style guides now prefer institutional knowledge or undocumented knowledge, on the grounds that tribal borrows from Indigenous peoples as a stand-in for informal or primitive. The underlying problem is unaffected by what it is called, and it is solved the same way: by making the knowledge inheritable instead of personal.
De onde vem
Entered common use through manufacturing and quality management, where it described the process knowledge held by veteran operators, and spread into software engineering. Timer treats it as a symptom of a missing memory layer rather than as a category of its own.