List concatenation is a process in programming where two or more lists are combined to form a single list. This operation allows for the merging of data, making it easier to manage and manipulate collections of items. In many programming languages, such as Python, concatenation can be performed using the `+` operator. For example, if you have a list of fruits, like `['apple', 'banana']`, and another list of vegetables, like `['carrot', 'lettuce']`, concatenating these lists would result in `['apple', 'banana', 'carrot', 'lettuce']`. This technique is useful for organizing data and simplifying code.