Holy Tradition is the deposit of faith given by Jesus Christ to the Apostles and passed on in the Church from one generation to the next without addition, alteration or subtraction, which can be described as "the life of the Holy Spirit in the Church." It is dynamic in application, yet unchanging in teaching. It is growing in expression, yet ever the same in essence. It is "the faith that was once for all delivered to the saints" (Jude 1:3).
Contrary to the popular understanding of the term, Holy Tradition is NOT something which grows and expands over time, forming a collection of practices and doctrines which accrue, gradually becoming something more developed and eventually unrecognizable to the first Christians. Rather, Holy Tradition is that same faith which Christ taught to the Apostles and which they gave to their disciples.
The central location in Holy Tradition is occupied by the Holy Scriptures, the written witness to God's revelation in the Church. As such, the Scriptures are always interpreted from within the Tradition which was the context for their writing and canonization.