The word Mer-Ka-Ba is made up of three smaller words, Mer, Ka and Ba, which, as we are using them, came from [the] ancient Egyptian[s]. It is seen in other cultures as merkabah, merkaaba and merkavah. There are several pronunciations, but generally you pronounce it as if the three syllables are separate, with equal accents on each. Mer refers to a specific kind of light that was understood in Egypt only during the Eighteenth Dynasty. It was seen as two counterrotating fields of light spinning in the same space, which are generated by certain breathing patterns. Ka refers to the individual spirit and Ba refers tot he spirit’s interpretation of its particular reality. In our particular reality, Ba is usually defined as the body or physical reality. In other realities where spirits don’t have bodies, it refers to their concepts or interpretation of the reality they bring with them.

Source: Drunvalo Melchizede. The Ancient Secret of the Flower of Life: An Edited Transcript. Volume 1. pg. 4-5. 1998.