This dictionary aspires to be a legislators “manual” and an indispensable companion. It contains over 500 entries of basic words any legislator must know and use. These words are drawn from Constitutions, Interpretation Acts, Standing Rules of the Senate and other Legislative Houses in both Parliamentary and Presidential Systems practiced by Nigeria, United Kingdom and United States of America. The basis for this comparison and collation of legislative terms from both parliamentary and presidential systems is the acceptance of the doctrine of Sir William Dale that legislative terms and solutions are universal and therefore applicable across jurisdictions irrespective of whether they are civil law or common law jurisdictions. Besides the main entries, the dictionary presents vital information on law-making process from a variety of sources such as judicial cases, journals, and articles. Recent Supreme Court decisions on legislature or law-making are cited in this dictionary.