BUDDHA

The popularly known Buddha is Siddharth Gautam Buddha who is known to have  propounded modern Buddhism. See Buddha Gautam.  But, in Buddhist pantheon, there are mention of many Buddhas under various schools of Buddhism. The  following series of Buddhas are worth mentioning for general  understanding of the theory of Buddhahood: Adibuddha or the original Buddha; Dhyani Buddhas or the meditating Buddhas; and, Manushi Buddhas or The Mortal Buddhas
Adibuddha or Swayambhu or Vajradhara or Samantha Bhadra is the abstract concept of the Ultimate Reality, which, the Vajrayana school of Buddhism equates with Void or Nothingness or Shunyata. This is to imply that this is a state of being of perfect spirituality, totally free from any existential or phenomenal bonds. The Dhyani Buddhas emanated from Adi Buddha. The five Dhyani Buddhas or the Pancha Buddha with five different colours, aspects, roles and characteristics are the important names of the dhyani Buddhas. There are some other Dhyani Buddhas as well in the Buddhist pantheon such as Buddha Bipaswi, Buddha Kanakmuni, Buddha Krakuchhanda etc. Dhyani Buddhas are always shown seated in the posture of meditation known as Dhyanasana or Bajrasana or the lotus posture known as Padmasana.
Siddharth Gautam Buddha is the Manushi Buddha or the mortal Buddha. There are all possibilities for all beings to be a Buddha by practicing the thoughts and practices of the eight-fold path shown by the Buddha.