In polar coordinates each point can be defined by its radius and two angles: $(r,\theta ,\varphi )$, the relationship with the cartesian coordinates can vary but I would use:
$$x=r\sin(\theta)\cos(\varphi) $$ $$y=r\sin(\theta)\sin(\varphi) $$ $$z=r\cos(\theta) $$
I would like to know the name of this angles. I have seen that $\varphi$ is called colatitude or zenith but $\theta$ is just referred as "the angle".
Short and sweet, here's what I've been calling them :
$\theta$ is "polar angle" or "colatitude" $\in [0,\pi]$ (indeed the regular latitude $\in [-\pi/2,\pi/2]$)
$\varphi$ is "azimuth" or "longitude" $\in [0,2\pi]$
I have seen french people call $\theta$ the "zenithal angle" but only rarely