What is the name of centre of mass speed of an aircraft? I have a list of positions (X [NM], Y[NM], Z[NM]) of an aircraft. Every coordinate is given every 1 second.

I calculate the speed [knots] between two consecutive coordinates in the following way:

$S_{i+1}=\frac{\sqrt{(X_{i+1}-X_{i})^2 + (Y_{i+1}-Y_{i})^2 + (Z_{i+1}-Z_{i})^2}}{1s}3600\frac{s}{h}$

It's basically space over time.

Does this 3D speed have a specific name?
It describes what the velocity vector of the aircraft centre of gravity is in relation to the surface of the earth. Ground speed is the 2-D projection of your speed on the ground, climb speed is the vertical component.

Both ground speed and climb speed are very useful parameters as such: ground speed to figure out when the aircraft arrives, climb speed to adjust engine settings etc for reaching cruise altitude with a minimum amount of fuel used. The 3-D vector sum of the two has little practical use, that is probably why it has no separate name as far as I know.

The integrated signal is of more use: what is the position in 3D of the centre of gravity of the aircraft relative to earth? Pretty useful for navigation.