Interface Segregation Principle
ISP
A software design rule holding that no client should be forced to depend on methods it does not use — large interfaces should be split into smaller, more specific ones so each client only knows about what it needs.
Origin
Robert C. Martin formulated the Interface Segregation Principle in the 1990s while consulting for Xerox on printer software that had grown into a single, bloated interface. He published it as one of his core design principles in his 2000 paper "Design Principles and Design Patterns." It later became the "I" in the SOLID acronym, coined by Michael Feathers around 2004.
Everyday Use
Think of a TV remote with 80 buttons when you only ever use five. A better design would give you just the buttons you need. The same logic applies to software, menus, and even workplace procedures — forcing people to deal with options they'll never use adds confusion and slows everyone down.