"The word Merkaba is actually composed of three separate words: Mer, which means light, Ka, which means spirit and Ba, which means Body. Put together, these three words connote the union of spirit with the body, surrounded by light. The symbol, which takes the shape of a star, is believed to be a divine vehicle made entirely of light and designed to transport or connect the spirit and body to higher realms. Ancient Jewish texts reveal that the word is also the Hebrew for a chariot, and the Bible reveals that the word Merkaba itself is found in the Old Testament a total of 44 times.
It is said that the symbol is composed of two-star tetrahedrons, which consists of counter-rotating fields of light and energy that surrounds each person. This energy extends beyond the body. Some believe that even planets have this Merkaba energy field around it." - ancient-symbols.com
Sorry friends, I got lazy writing the description on this one, but there wasn't much to improve on so I copied the above information that pretty much says what I was wanting to share.