Question: "What's the working definition of "tradition" as far as the Church is concerned?"
The English word "tradition" comes from the Latin word "traditio," which corresponds closely with the Greek word we find in the New Testament, "paradosis". The word itself literally means "what is transmitted." It is the same word used when referring negatively to the false teachings of the Pharisees (e.g. Mark 7:3), and also when referring to authoritative Christian teaching (1 Corinthians 11:2, 2 Thessalonians 2:15). So what makes the traditions of the Pharisees false and that of the Church true? The source! Christ made clear what was the source of the traditions of the Pharisees when He called them "the traditions of men" (Mark 7:8). Saint Paul on the other hand, in reference to Christian Tradition states, "I praise you brethren, that you remember me in all things and hold fast to the traditions [paradoseis] just as I delivered [paredoka, a verbal form of paradosis] them to you" (1 Corinthians 11:2), but where did he get these traditions in the first place? "I received from the Lord that which I delivered [paredoka] to you" (1 Corinthians 11:23). This is what the Orthodox Church refers to when it speaks of the Apostolic Tradition — "the Faith once delivered [paradotheise] unto the saints" (Jude 3). Its source is Christ, it was delivered personally by Him to the Apostles through all that He said and did, which if it all were all written down, "the world itself could not contain the books that should be written" (John 21:25). The Apostles delivered this knowledge to the entire Church, and the Church, being the repository of this treasure thus became "the pillar and ground of the Truth" (1 Timothy 3:15).
Within the Church, we use the word "tradition" in a number of senses. Though we often speak of Scripture and Tradition as being two different things, there is a very real sense in Which Scripture is also Tradition. Much of Scripture existed in oral form before it was written down, and in some cases the gaps or hundreds and even thousands of years -- and so prior to being written down, these were oral traditions. Furthermore, Tradition has passed on what should be recognized as Scripture, Tradition has passed on the meaning of Scripture, and Tradition has in fact passed on the very text of the Scripture.
After Scripture, Apostolic Tradition is without doubt the highest form of Scripture, and it is from Apostolic Tradition that we derive the core of our liturgical and canonical practices, and even such things as making the sign of the Cross, facing east at prayer, and baptism by triple immersion, as St. Basil the Great points out in his treatise On the Holy Spirit, Chapter 27.
There are also what we could call Ecclesistical Traditions, which are not directly based on Apostolic Tradition, but which have been affirmed by the universal Church, and so are no less trustworthy. Such Traditions would include the canons and decrees of the Ecumenical Councils, as well as the canons of local councils and Fathers of the Church that have been affirmed by the Ecumenical Councils. This would also include universally received Liturgical Traditions.
Then there are what you could call local traditions -- and here we are getting into traditions that could also be categorized as "customs." For example, in the Russian Church, it is the tradition to kiss the chalice after you receive Holy Communion. In the Greek Church, they do not kiss the chalice. Both of these practices are motivated by a common piety regarding the Eucharist, but are expressed in opposite ways. Neither custom is superior to the other, but when in Rome, one should do as the Romans do, and in the context in which one custom prevails or the other, one should respect that practice. But clearly, we are not talking about infallible traditions of the universal Church.
There is a popular distinction that is sometimes made between "big T" traditions" and "little t" traditions. I think this distinction is not far off, so long as one is careful about what they label as "big T" or "little t" traditions. I personally don't use this distinction, because I have too often seen people try to dismiss universally received traditions as "little t" traditions.
Another important distinction that should be understood is that there is a big difference between saying "The Tradition of the Church is..." and "There is a tradition...." For example the Tradition of the Church teaches us that we should baptize by a triple immersion, and that is not something that you can either take or leave. There is a tradition that Christ travelled to England as a boy, which may or may not be true.
So a tradition can either be a good and binding tradition, a bad and erroneous tradition, or a good local custom, but with a relative authority. The key questions are, what kind of tradition are we speaking about, what is its origins, and how universally received is the tradition in question? But when we are speaking of Apostolic Tradition, or Traditions which have been universally received, these are Traditions that we are to hold fast to, just as St. Paul tells us (2 Thessalonians 2:15).
See Also: Stump the Priest: Are Ecumenical Councils Infallible?
