I take it you mean a regular pie crust vs. tart!
A tart dough is closer to a cookie-like dough as opposed to a flaky pie crust.
A tart dough is usually on the sweet side and the ingredients include flour, sugar, salt, butter, egg yolk and water.
Tart doughs can also be made with ground nuts.
There's also a classic Alsatian tart dough (unsalted butter, sugar, salt, whole eggs, vanilla extract, grated orange zest and flour)
A regular pie crust includes flour, salt, a fat (either shortening/lard, butter or a combination), and water. An acid can also be added (vinegar, lemon juice...)
Hope this helps.