Of course, this isn't the technical sense of tradition, and the term itself is ubiquitous in biblical scholarship. In fact, tradition as an analytical concept is in need of some precision; in the current environment it's only too easy to write whole books on some aspect or other of tradition without ever really spelling out precisely what we mean by it.
Vincent Taylor, in his famous book, The Formation of the Gospel Tradition (London: MacMillan and Co., 1933), reflects on the term explicitly on the very first page. There's much to disagree with here, especially eighty years after the book was published. But it is helpful for thinking about how far thinking about tradition has come.
It is important that we should appreciate the distinction between the 'Gospel tradition' and the Gospels. Before the Gospels were written the 'tradition' was organic; it was a thing of life, and as such was always changing and growing. Just because of this it was subject to the accidents and experiences of life; it could be corrupted, but it was also capable, through growth and change, of becoming more truly itself, as the sapling grows into the tree and as the child becomes the man. In the Gospels the 'tradition' has attained a relatively fixed formation; it is no longer subject to change, except as it is altered by copyists or by the writers of the later Apocryphal Gospels. Whenever we return to our Gospels we find the tradition as we left it, and the only changes which can happen are those which take place within our own minds through fuller knowledge and understanding. Before these books were written the position must have been very different. At that time the tradition was more plastic; it was a story of life and a product of life; its formation was determined by its contents and by the mental and spiritual environment in which it lived; it grew, and developed, and had a history. (1–2)
Many people recognize that tradition (as distinct from texts, as Taylor is using the term) is hardly made static or fixed by virtue of being written down. Certainly Matthew and Luke, if they knew of and used Mark as a source for their own gospel texts (the standard position among NT scholars) did not think of the tradition in Mark's gospel as "fixed" or "static." And the early Christians who recognized these texts as the word of God did not, apparently, experience angst at the variation and fluidity of the tradition as evident across the three synoptic gospels, to say nothing of John's gospel (!). However counterintuitive it may seem to us that tradition remains "organic," vibrant and adaptable, even in written form, this seems to be the clear perception of the texts among the early Christians. It may seem weird to us, but I suspect that, if they could analyze us, our own preoccupations with the verbal fixation of written/printed texts would seem equally alien.