OK, in the book I mentioned earlier, David Currie breaks Church information down into five different groups: deposit, dogma, doctrine, discipline and devotion. He defines them as follows:
Deposit–the body of truth originally given to the Apostles, some of which was later written down, while some of it remained in its original form of oral tradition. The goal regarding the deposit is simply to maintain it with no change whatsoever.
Dogma–that body of truth that has been affirmed by the Councils of the Church and the Holy See in Rome. It is the further explanation, development or definition of concepts found within the deposit. Once dogma is declared, it can be further developed but never contradicted by future doctrine or dogma.
Doctrine–the development of truth on the basis of the deposit and dogma. **Doctrine can develop and even contradict itself over time because it is largely the thoughts of people. ** It has not been officially declared true or false by the Church.
Disciplines–those rules that govern the everyday life of faithful Catholics. This area has seen the most change since Vatican II. An example: the change in which days Catholics are required to fast from originally 12 days known as Emberdays, to what is now essentially just Ash Wednesday and Good Friday.
Devotions–those activities by which an individual Christian may enhance their walk with God. Devotions are never mandatory for a Catholic layman, although they may be approved and are highly recommended. A well-known example: the Rosary.
Anyways, I hope that helps.