What does Post means in animation?

Hi, I am new here.
I found there are many Pose in animation system:
Cache pose
Poseable_mesh
and AlwaysTickPoseAndRefreshBones in EVisibilityBasedAnimTickOption
I am confused, are there pose same thing?
what is the diff between bone transform and pose?

Thanks

pose is used in the state machine for player control
there are also separate metahuman skeletal mesh poses
they are different