PLAIN-LANGUAGE DEFINITION
Safe zone
A safe zone is an area reserved for important content away from likely crops or interface overlays.
IN PRACTICE
An example
Keep key text near the center of a portrait composition and preview it in the target app.
What this does not tell you
Platform interfaces change; a generic overlay is a guide rather than an official specification.
Use the term precisely
When you use this term in a brief or report, include the relevant source, scope and assumptions. An example explains the concept; it is not a benchmark or a promise of results.