Lawyers use words or phrases with very specific legal meanings. Many terms and phrases, such as "right to silence", may be used in legal writing without being defined as it is assumed that the reader will be familiar with the terminology. For the new law student, it is vital that you consult a legal dictionary for any terms you need to define or clarify.
For any research topic you need to understand the legal meanings of the terms used. Without an accurate understanding of what the terms mean, you may misinterpret the topic. You may also find it difficult to compile a list of keywords (search terms).
The standard used by Australian courts and government departments is the Macquarie Dictionary (AGLC4 rule 1.9.1).
Macquarie Dictionary online is constantly updated with words as they enter our language, covering English as it is used in Australia from the colloquial to the technical.
Oxford English Dictionary online is the full text version of the 20 volume print edition.