A row of numbered places
Think of a shopping list: apples first, bread second, milk third. An array stores items in a sequence. A program can go through the whole list or ask for the item at a particular position. In many programming languages, the first position is numbered zero.
Arrays are useful for ordered results such as search matches. Adding or removing an item in the middle may mean shifting other items. “List” is often used informally for an array, though some languages give lists a different technical meaning.