What does each of the letters stand for F=d^2s/dt^2?

I know F stand for force, the rest don't know.

Well force F = rate of change of momentum P

momentum P = mass * velocity = m V
so
F = d/dt P = d/dt ( m V)
if mass is constant (usual assumption in rigid body physics at speed much less than light speed
F = m dV/dt
BUT
V = dx/dt where x is position
so
F = m d^2 x/dt^2
I suspect that this is what you intended to write
however if s = m x
then what you typed works

x

In the equation F = d^2s/dt^2, the letters have the following meaning:

F: This represents force. In physics, force is the push or pull experienced by an object due to the interaction with other objects.

d: This symbol represents the differential operator, which is used to find the instantaneous rate of change.

s: This represents the displacement of an object. Displacement refers to the change in position of an object with respect to time.

dt: This represents the differential of time. It is used to indicate a small change in time.

To interpret the equation, you can read it as "The force (F) is equal to the second derivative (d^2) of the displacement (s) with respect to time (dt)." This means that the equation describes how the force acting on an object is related to how its displacement changes over time.