Basic Forms
* tract: a region of land, especially one having a particular characteristic
* tractate: a treatise or formal discourse
* tractable: easily managed or controlled
* intractable: difficult to manage or control
* tractrix: a curve in geometry
Derived Forms
* attract: to draw or pull towards something
* contract: to make or become smaller
* detract: to take away from the value or importance of something
* extract: to remove or take out something
* protract: to lengthen or draw out in time
* retract: to take back or withdraw something
* subtract: to take away from something
* abstract: a summary of a longer work
* contraband: goods that are prohibited by law
* district: a region or area marked off for administrative purposes
* extract: to remove something, especially by force
* tractarian: a member of the Tractarian movement in the Church of England
* contractility: the ability to contract or become smaller
* attractiveness: the quality of being pleasing or desirable
* retractility: the ability to retract or withdraw
This list isn't exhaustive, but it gives you a good starting point for exploring words with the "tract" root.