The process by which meaning and content are given, by the courts, to statutes and the words and phrases contained in them. This process is aided by various rules and presumptions, such as the literal, mischief and purpose rules, and recourse to extrinsic materials relating to the particular statute in question.
(Encyclopaedic Australian Legal Dictionary, 2016)
The choice of dictionary matters. Oxford and Macquarie are considered reliable dictionaries for obtaining the ordinary meaning of a word.
Use a legal dictionary when the legal meaning is required.