According to Nepalese, “Adi-Buddha” is the original Buddha who is without beginning and without end. He is said to be infinite, self created, and revealing himself in the form of a blue flame coming out of lotus. In Nepal, Swayambhu is worshipped as Adi-Buddha.
According to Hebrew, “Adi” represents Jewel or ornament. This name is given to both boys and girls.
According to Old German version, “Adi” means noble.
This what I found so far. If you know any other meaning behind “Adi”, please do comment.