The Timestream is a point in space-time where all past, present and future timelines meet and intersect. It is a place where the timelines branch and shift.
The timestream resembles a giant tree that has luminescent outlinings and a mixture of navy and black where there isn't any luminescent outlinings.
Through direct travel in the timestream, one can appear anywhere in space and time.
Indirect travel through the timestream is possible with the creation of shortcuts like portals or through teleportation, as is the case with Professor Paradox, Chronosapiens, technology like time machines and in some cases through magic.
Constant shifts in the branching timestream occurs and time travelers can end up in another past, present and future timeline and travel into cross time making time travel tricky business.
History can be changed and rewritten in the timestream. Time wars had been fought over the timestream.