Or you could just praise your own language and write what it means "and so forth". Or "et cetera". An abbreviation should, in my opinion, only be used when it is absolutely necessary or required to shorten the text; as in a sms, twitt or in relation to graphic layouts and so forth.

You don't abbr. abbreviations either, right.

In any case, I wouldn't do two periods, either. But then again, I wouldn't do it at all.

Dear Johannes,

Thanks very much for your comments and answer to my question. I do understand that abbreviations should be avoided in academic writing. Your answer confirms my opinion that when it's necessary to use the abbreviation 'etc', two periods isn't an accepted style.

Cheers,

Jack.

You may write et cetera, etcetera or etc. without double period. However, it is interesting to note when writing on Microsoft Word, etc.without comma often results in automatic capitalisation of the first letter of the next word in the mid of the sentence.

Thanks Jana and Mohammad!

I do not recommend the use of "etc" because it indicates a lack of interest keep writing, is the equivalent of blah blah blah in an informal chat.

And I mean in an academic work only.

Thanks Eduardo! I was primarily referring to the use of 'etc.' in figure legends or methods protocols, and less formal academic work. I completely agree, that it should be avoided, if possible. Cheers, Jack.

Many formal standards don't allow the use of 'etc' (for exampla, APA referencing standards won't accept it) and will instead ask you to write "and so forth".

For less formal standards where you want to appear coherent and consistent, but there isn't a particular need to meet a set guideline, I would recommend using the Guardian Style Guide. http://www.guardian.co.uk/styleguide This is provided for its writers so they use all language consistently. It is similar to the New York Times style guide, but the NYT one is only available in print.

The Guardian Style Guide suggests that you omit the period after 'etc' throughout your work. This means you only add one period after 'etc' if it is at the end of a sentence.