Polymorphism
/ˌpɒl.iˈmɔːr.fɪ.zəm/ · Noun · Development
Definitions
The ability of different types to respond to the same interface — a function or method behaves differently depending on the type of object it's called on, while the calling code doesn't need to know the specific type.
In plain English: When different things respond to the same command in their own way — like how 'play' means different things to a guitar, a drum, and a piano, but you can tell any instrument to 'play.'