# Definition:Tangent Bundle

Let $X$ be a differentiable manifold.
The tangent bundle of $X$ is the disjoint union of all the tangent spaces of $X$ at $x$ as the base point $x$ ranges over the entire manifold:
$\displaystyle T \left({X}\right) = \coprod_{x \mathop \in X} T_x \left({X}\right)$