In computer science, a queue is a particular kind of abstract data

type or collection in which the entities in the collection are

kept in order and the principle (or only) operations on the

collection are the addition of entities to the rear terminal

position, known as enqueue, and removal of entities from the

front terminal position, known as dequeue. This makes the queue

a First-In-First-Out (FIFO) data structure. In a FIFO data

structure, the first element added to the queue will be the

first one to be removed. This is equivalent to the requirement

that once a new element is added, all elements that were added

before have to be removed before the new element can be removed.

Often a peek or front operation is also entered, returning the

value of the front element without dequeuing it. A queue is an

example of a linear data structure, or more abstractly a

sequential collection.

Representation of a FIFO (first in, first out) queue


[Wikipedia](https://en.wikipedia.org/wiki/Queue_(abstract_data_type))