Rotuli Parliamentorum; Ut et Petitiones, et Placita in Parliamento. Earliest official records of the meetings of the Parliament; reigns of Edward I through Henry VII (1278-1503).
Chancery Rolls - Medieval source material.
Parliamentary debates (often referred to as Hansard, the publisher since the nineteenth century) are records of what is said in Parliament, roughly equivalent to the U.S.'s Congressional Record. Only since 1909 has Hansard been a verbatim report and official publication; before then, publications were based on secondary sources such as newspaper accounts. See this link from Parliament for more information and this guide from the University of Missouri.
Journals are the official records of what is done in Parliament, roughly equivalent to the U.S.'s Daily Digest of the Congressional Record. The provisional records that are the basis for the Journals are Votes and Proceedings of the Lords. See this link from Parliament for more information.
An Act of Parliament is a law. See this link from Parliament for more information.
See this PDF file from Duke University for a very detailed guide to English legal history.