lineage: A line of descent from a particular holy source and all those associated with this lineage.
A lineage is a group of teachings or practises handed down from teachers to their students, who become teachers in their own right.
There are also ordination lineages: that is the line or ordination (monks and nuns) which is always traceable back to the Buddha.
Lineage is considered important in Buddhism, particularly in the Zen and Tibetan tradition where the master or guru occupies the main role in spiritual development.
There are some practices, meditations and texts which may be learnt from secondary sources, such as books, and some which must be given directly.
But before teaching any of these, a person should have received authorization or permission to teach.
The giving of this permission is dependent on spiritual understanding and attainment: almost never is it a political or allegiance matter.
Lineages are traceable back to the Buddha or sometimes, to a great and acknowledged master.
New lineages are started by people who are regarded as masters by those few masters in each generation who are considered extraordinary.