How many bicameral legislatures are there?

Once a body has been defined as a legislature, it can then be identified as being either unicameral or bicameral. Listing those legislatures that have a single chamber and those that have two should, therefore, be a straightforward task. However, there is some ambiguity as to what constitutes a second chamber. Three examples are offered of legislatures that are formally defined as unicameral but which exhibit characteristics of bicameralism. The examples are those of Botswana, Iran and the European Union. They serve to raise the question of whether the number of legislatures listed as bicameral should be increased and what we understand by the term second chamber.