An Array is a group of items stored next each other in memory. It's used as a bag or container of elements. Arrays are the most common datastructure in most languages.
In Object Oriented Programming, an abstract class is a class that is not completely implemented. A child class can inherit from the abstract class and implement it.
Repository Pattern is an abstraction layer between the application business logic and persistence ( database ) layer. Rather than scattering data access logic across the application, It's accessed through the Repository layer.
A Background job is a functions that runs in the background with a periodical interval e.g every 1 minute. Background jobs are very useful for batch jobs.
A Queue system is a system that stores the client requests in a queue until they are fetched and processed in the future when appropriate.
Pagination is the process of dividing your content into pages, this happens when you have a website and want to navigate between content easily.
In object oriented languages that uses garbage-collection, a finalizer is a special kind of method that does finalization and clean up of object.
Memory is divided into the Stack and the heap. Boxing happens when a value type is allocated on the heap. while Unboxing is getting it back into the stack.