Index: An index refers to the position at which an element is stored within a data structure like an array or list. It starts from 0 for the first element and increments by 1 for each subsequent element.
ArrayList: An ArrayList is a resizable array that stores elements of a specific type. It allows dynamic adding and removing of elements, making it useful when the size of the collection may change.
Traversal: Traversal refers to the process of accessing each element in a data structure, usually in a sequential manner. In relation to an ArrayList, it involves iterating through all the elements stored within it.