This is an abbreviation of the Latin et cetera, meaning 'and other things'. Some people say that it should not be used with lists of people, or to mean 'and so forth' when referring to events or actions: The children laughed, shouted, ran about, etc. However, its use in these contexts is well established, although et al is more polite when referring to people (this is an abbreviation of the Latin et alii, meaning 'and others').