How to cite simple definitions when writing university papers?

Question

When writing any kind of paper or homework at the university I am supposed to give references for my citations. At the same time, sources like Wikipedia are not considered good for university level. Now let's say I am writing about malware, and I want to give definition about virus. Wikipedia has a good explanation, but I obviously cannot just copy without references (right?), and to give reference to Wikipedia is considered unacceptable.

So how am I supposed to give reference to such an item? Am I supposed to change the sentence in such a way that it cannot be tracked where I took it from?

Answer 1

Standards for papers and homework is not the same as for publications. Moreover, there is nothing fundamentally right or wrong about a definition as long as you introduce it as such ! (in University words mean what you decide they mean -- within reason, that is). You can definitely write something like

In this paper I will use the definition of a virus as a '...' (1)

and refer to a footnote that says

(1) definition taken from Wikipedia article Virus, retrieved on 2014-10-04".

Of course if Wikipedia's definition is taken from a printed reference, use the latter.

If you want to be extra-cautious you can have a look at the change log and discussion of the Wikipedia article.

Answer 2

Two points to remember:

1) Always give a reference for anything which is not your own! Changing the sentence in such a way that it cannot be tracked is NOT an acceptable substitute.

2) For as long as you are a student, the university sets the rules for what is considered an acceptable source.

Since your university, like many others which I am familiar, does not consider Wikipedia to be an acceptable academic resource, you should not cite Wikipedia in papers/homework. (When writing for an audience other than your professor(s), you be the judge. This question provides a nice overview of the pros and cons of citing Wikipedia.) For the example you've given, the relevant Wikipedia page has many linked references. The usual workaround is to follow those references, find one which contains the definition you need, and cite that reference rather than Wikipedia. Of course, as JeffE noted, be sure you've actually read the source you are citing!