Space of stochastic process $\mathcal M (\mathcal C [0, T], E)$

Space of stochastic process $\mathcal M (\mathcal C [0, T], E)$

A simple notation question, what is the precise definition of the space
$\mathcal M (\mathcal C [0, T], E)$ ($\mathcal M^p (\mathcal C [0, T],
E)$) in the context of stochastic processes where $E$ is a banach space (
$\mathbb R ^d$ or $\mathbb L^p_{\lambda}(\Gamma)$ for example)?
In the article I read, this notation is introduced without definitions,
seeming so to be pretty standard. In addition what is the mean of
$\mathcal M (\mathcal C( [0, T], E))$ and what is the difference between
the previous space?
Thanks in advance