Quick answer
The code used to authenticate to the device and, where offered, to controls protected by device authentication.
Limitation
Someone who knows it may have a fallback route to information you thought was protected only by biometrics.
Related terms
Questions
What does Device passcode mean?
The code used to authenticate to the device and, where offered, to controls protected by device authentication.
What limitation matters?
Someone who knows it may have a fallback route to information you thought was protected only by biometrics.