A first reading is when a bill is introduced to a legislature. Typically in the United States, the bill is assigned a tracking number and immediately assigned to a committee, and is amended by committee between the first and second readings. In most British influenced legislatures (see: Westminster system), the committee consideration occurs between second and third readings.
In Canada, first reading of a bill can occur in either the Senate or House of Commons in the federal parliament. Since the provincial legislatures are unicameral, first reading occurs in the sole chamber of those parliaments. The bill is then printed.
In Ireland, the first reading is referred to as "First Stage", and is leave to introduced a bill into a House of the Oireachtas. It can be taken in either house, though does not need to be taken in both.
A second reading is the stage of the legislative process where a draft of a bill is read a second time. In most Westminster systems, a vote is taken in the general outlines of the bill before being sent to committee.
In Canada, second reading occurs in Parliament. Members debate and vote on the principle of the bill. The House may decide to refer the bill to a legislative, standing or special committee, or to a Committee of the Whole for consideration (clause-by-clause study of the bill). The Committee may summon witnesses and experts to provide it with information and help in improving the bill. The committee then reports the bill to the House clearly indicating any amendments proposed. The house then considers amendments, voting for or against them.
In Ireland it is referred to as Second Stage, though the motion at second stage is still "that the Bill be read a second time", as in some other Westminster systems. A bill introduced in one house enters the other house at Second Stage. Once the bill passes second stage it is referred to a Select Committee of that house or taken in Committee Stage by the whole house.
The different roles of the second reading are in part a reflection of the different powers of legislative committees. Legislative committees are far more powerful in the United States than in Westminster systems.
A third reading is the stage of a legislative process in which a bill is read with all amendments and given final approval by a legislative body. In legislatures whose procedures are based on those of the Westminster system, the third reading occurs after the bill has been amended by committee. In most state legislatures and the Congress of the United States, a third reading occurs only if the two legislative houses pass differing versions on second reading and those differences must be resolved by conference committee. Third reading is unnecessary in the United States when the versions of the bill passed by both legislative houses are identical. In each house of the New York State Legislature, the third reading is necessary before either house may pass a bill; often a bill reaches the order of third reading but is not ultimately passed.
In the Parliament of Canada, if the bill passes the third reading, it is then sent to the other chamber of parliament to start the process again at first reading in that chamber. The final step, after passing third reading in both chambers, is Royal Assent. In the unicameral provincial legislatures in Canada, after passing third reading in the sole chamber, the bill goes directly for Royal Assent.
In Ireland the third reading is referred to as "Report and Final Stages". These are normally taken together. The question at final stage is "that the bill do now pass", as for the third reading in some other Westminster systems. When it passes one house, it is sent to the second house and enters at Second Stage. After both houses have passed the bill, it is sent to the President of Ireland to be signed into law, if there is a question regarding the constitutionality of the bill she may refer it to the Supreme Court of Ireland, otherwise she cannot withhold assent. In Canada, the bill is recited 5 times to ensure all members of parliament are familiar with it before it receives final approval.