From The Dhamma Encyclopedia
Paccekabuddha (Pāli), literally "a lone buddha" , "a buddha on their own" or "a private buddha", is one of three types of enlightened beings according to some schools of Buddhism. The other two types are the Samma-sam-buddha and Arahant. They are said to achieve enlightenment on their own, without the use of teachers or guides, according to some traditions by contemplating the principle of dependent arising. They are said to arise only in ages where there is no Buddha and the Buddhist teachings, the Dhamma are lost. Many may arise at a single time. Unlike Supreme Buddhas, their enlightenment is not foretold.
Some schools assert that pratyekabuddhas are not omniscient, while others say that they are the same (in realisation) as Bodhisattva Buddhas, but do not have the will to teach the entire Dharma. They do give moral teachings, but do not bring others to enlightenement. A pratyekabuddha leaves no saṅgha as a legacy to carry on the Dhamma.
Pratyekabuddhas (e.g. Darīmukha J.378, Sonaka J.529,) appear as teachers of Buddhist doctrine in pre-Buddhist times in several of the Jātakas. The experiences and enlightenment-verses uttered by Pratyekabuddhas are narrated in the Khaggavisāna-sutta of the Sutta Nipāta.
The yāna or vehicle by which pratyekabuddhas achieve enlightenment is called the pratyekayāna, the "on-one's-own vehicle", in Mahayana tradition.
In the Majjhima Nikāya of the Pāli Canon it says that offerings to Pratyekabuddhas are superior to offerings to Arhants and also that offerings to Tathāgatas are superior to offerings to Pratyekabuddhas. This may imply that Pratyekabuddhas are superior to arhants but inferior to Tathāgatas in realization.