36 First, it may be accepted that the question whether a word in a statute is to be given its ordinary meaning or a technical or defined meaning is a question of law: Collector of Customs v Agfa-Gevaert Ltd  HCA 36; 186 CLR 389 at 395, referring to the first proposition in Collector of Customs v Pozzolanic Enterprises Pty Ltd (1993) 43 FCR 280 at 287. Thus, if the magistrate gave the word a limited meaning in circumstances where, as a matter of law, it had a broader meaning, there would have been an error of law. However, as noted above, the definition in cl 6(7) does not, on its face, purport to exclude any object which would fall within the category of “walls”, in the ordinary sense of that word. Nor did the primary judge expressly explain how a structure which would be a wall in the ordinary sense, would not fall within the defined term. Further, and secondly, had she done so, she should have remitted the matter to the magistrate for him to determine whether or not the mesh screens fell within the ordinary meaning of the term “wall”. That is because the ordinary meaning of the word is a question of fact: Agfa-Gevaert at 395, second principle identified in Pozzolanic . The only circumstance in which it would have been appropriate for her Honour to determine the question would have been if only one answer were available. Her Honour did not so hold.
37 Thirdly, her own reasoning was erroneous. For the ordinary meaning, her Honour turned to definitions of “wall” in the Macquarie Dictionary and in the Oxford Dictionary . The value of a dictionary in providing common (and indeed uncommon) uses of words is undeniable; the pitfalls with respect to their use in statutory construction derive from their strengths. A common word may have a core meaning, but it may also be used analogically, figuratively, metaphorically and sometimes merely to raise illuminating associations. The danger was famously identified by Judge Learned Hand in Cabell v Markham (1945) 148 F.2d 737 at 739:
“But it is one of the surest indexes of a mature and developed jurisprudence not to make a fortress out of the dictionary; but to remember that statutes always have some purpose or object to accomplish, whose sympathetic and imaginative discovery is the surest guide to their meaning.”
38 The importance of this approach, cited with approval in Residual Assco Group Ltd v Spalvins  HCA 33; 202 CLR 629 at , is reflected in the obligation to adopt a construction of a statute which would “promote the purpose or object underlying the Act”:Interpretation Act 1987 (NSW), s 33. As the Club submitted, walls have many purposes and effects; the Act is concerned with their effect in aggravating the exposure of both smokers and other persons to tobacco and other smoke where they operate to enclose a public place: s 3, Object of Act. That purpose must be borne steadfastly in mind in determining the meaning of the language in the statute, both generally and in relation to the word “wall”. Her Honour did not adopt that approach, as appears from the conclusion reached at :
“The first-listed definition from the Macquarie Dictionary is relevant in the present case. Importantly, it defines a wall by reference to functions going beyond the prevention or inhibition of lateral airflow (i.e. enclosure, division, support, protection, etc). When this definition is adopted, it is clear that the mesh screens were, collectively or individually, a wall or walls. They were upright metal structures designed to divide or enclose the Western Terrace from the loading dock area.”
39 This approach, relying on the great variety of functions that can be served by a wall, fails to focus on the particular function served in respect of a public place having a ceiling or roof. By contrast, and assuming that one is only concerned with the language of the 2007 Regulation for present purposes, there is good reason to accept the submission of the Club that a structure or device which does not, in a discernable way, impede lateral airflow, is not a wall for the purposes of the Act.