The term is an abbreviation of the Latin expression et cetera, which means "and other things". As it is an abbreviation, it should always be written with a period at the end. The word is normally used at the end of a series of enumerations, in place of the other elements that would fit in that list. It appears in everyday language constructions, as in the example: "Bought a pencil, eraser, pen, etc.". In that case, etc. indicates the rest of the school supplies. Considering its original, etymological sense, it should not be used to mention people. Therefore, in bibliographic references, when a book has more than one author, use, for example, João Camargo et al.. This expression is also Latin, but it means "and others", and is therefore the most suitable when it comes to people. Another interesting - and controversial - issue regarding the term is the need to use a comma before introducing it in a sentence. As it is an abbreviation of et cetera and the Latin et is equivalent to our conjunction "and", the comma is not necessary. The discussion, however, still divides theorists and there are those who defend its use, generally based on the frequency with which this type of construction appears in writing.