Inheritance is not oop. If you think about it inheritance is syntactic sugar around definitions of objects. Not really a programming style because it doesn't change the structure of your program in terms of state and logic. These are simply definitions, no control flow is defined here.

I have object a and I have object b. A is similar to b. How do I define a in terms of b? That is inheritance. Functional languages can support this type of syntactic sugar. It is not exclusive to OOP.