Is there a name for smooth map $\Pi:M\to\mathcal{L}(R^l)$ such that $\Pi(p)$ is an orthogonal projection and $\dim\Pi(p)$ is constant for all$p\in M$?

Question

I'm reading the book "Introduction to Differential Geometry" and according to the Theorem 2.6.10 (which is in the page 75), if $\Pi :M\to \mathcal{L}(\mathbb{R}^l)$ is a smooth map satisfying those conditions, then $E:=\bigcup _{p\in M}\{p\}\times \text{Im}(\Pi(p))$ is a smooth vector bundle over $M$. So I would like to know if this map has a name and if such maps appears in a more general context in the theory of manifolds.

Thank you for your attention!