Encapsulation or Data hiding or Information hiding.
In Object-oriented Programming Encapsulation is a technique to hide or restricted the access to the properties and behaviours of an object.
Also,
Encapsulation is a process of wrapping code and data together into a single unit, for example a capsule in which mixed of several medicines.
Encapsulation mechanism keeps the data and the code safe from external interference.
Example :
Access restriction to the properties and methods by using the keywords private, public, protected in a class.