In its baldest terms copyright means this: Protection for published works. Published works are basically anything that can be distributed an accessed by multiple users: books, journals, digital files, video etc. The purpose of copyright is to protect the rights of the entity that created the work in in the first place because creating work is work and work and this work should be recognised. Copyright is not for the purpose of locking things away, it is to ensure they are used fairly. In academia in particular but not exclusively, as long as works are cited properly and used in a reasonable and purposeful way, there should be very little problem. The most important thing to understand is just because something is available on the internet or in a library that it has no copyright attached to it. The responsibility always rests with the user of a piece of work to ensure that reasonable efforts have been made to not infringe the copyright of the owner of any work you reference or use.
Copyright licences are different for different pieces of work, so it is important to understand that too. Ultimately, citing properly, taking your content from reputable sources, making requests of copyright owners to use content and fair use will protect you. Plagiarism and copyright are not the same thing; copyright is a binding legal term, plagiarism is cheating.
This is a very handy resource in the form of a flow chart. This resource is from the USA and relates to the laws there, however, it does give you a good idea of how copyright work particularly in education.
Click on the image to view the chart.
Copyright Flowchart: Can I Use It? Yes? No? If This… Then… Silvia Rosenthal Tolisano June 10, 2014 Retrieved from