This is how Wikipedia defines the term Catechism:
A catechism (pronounced /ˈkætəkɪzəm/; Ancient Greek: κατηχισμός from kata = “down” + echein = “to sound”, literally “to sound down” (into the ears), i.e. to indoctrinate) is a summary or exposition of doctrine, traditionally used in Christian religious teaching from New Testament times to the present. Catechisms are doctrinal manuals often in the form of questions followed by answers to be memorized, a format that has been used in non-religious or secular contexts as well.
The Lutheran church uses Luther’s Small Catechism as the basis for its instruction of both children and adults. It contains questions and answers that are meant to give the student (catechumen) answers about what it is that we believe, teach and confess. Its teachings (as are all of the Lutheran Confessions) are drawn from Holy Scripture. In short, the catechism is a book with questions and answers that proclaim the truths of Scripture that brings salvation. In that spirit, this series of posts will be posed as questions with answers.
If you have any questions, just ask. I will reply personally to you and may even post as a separate blog post in the future.