The punctuation mark used to separate items in a list, as in “apples, oranges, and pears,” is a comma. It helps readers see where one listed item ends and the next begins.
Commas have several other jobs in English. They can separate introductory phrases, nonessential information, coordinate adjectives, and parts of some compound sentences. In a list, the comma usually appears between each item; a conjunction such as “and” or “or” normally introduces the final item.
The comma before the final conjunction is called the serial comma or Oxford comma. “Apples, oranges, and pears” uses it, while “apples, oranges and pears” omits it. Both styles are accepted, although particular publishers, schools, and style guides may prefer one. The Oxford comma can sometimes prevent ambiguity in longer or more complicated lists.
A semicolon may separate list items when those items already contain commas. A colon can introduce a list, but it does not normally replace the commas between simple items. A hyphen has different roles, such as joining parts of compound words.