Mer-Ka-Ba means the Spirit/Body surrounded by counter-rotating fields of Light (wheels within wheels), which is a vehicle to transport Spirit/Body from one dimension into another.
It can take on many forms of light. It is made up of 2 star tetrahedrons. We all have a merkaba field around us. One just has to activate it to connect with the higher dimensions.
Mer means Light, Ka means Spirit, Ba means Body