So what IS plagiarism?

According to the Faculty of Information Technology:

"The (legitimate) use of another person's work, with an (illegitimate) lack of due acknowledgment of the source of that work". (http://www.csse.monash.edu.au/~ajh/adt/policies/cheating.html)

What does that actually mean?

Using someone else's ideas or words in your own work and not acknowledging whose ideas/words they are.
For CSE1304, plagiarism is said to have occurred if you use more than six words in a row from another source without referencing them correctly.
You may NOT use anything from the web, newspapers, journals, books or any other media unless you reference your sources in an appropriate manner.
Your work will be checked using electronic plagiarism detection systems.
The penalties are set by the university and enforced strictly.
To avoid any problems you should reference correctly!