Hello daverupa, all,
A Samma-sambuddha rediscovers the Dhamma after it has ceased to exist in the world. Arahants do attain buddhahood as do pacceka-buddhas, and the term Savaka-buddha has been in use in Theravada since early in the history of buddhism.
Sāvaka-buddha (Pāli) is a rarely used term in Theravada Buddhism, identifying enlightened 'disciples of a Buddha' as Buddhas. These disciples are those enlightened individuals who gain Nibbana by hearing the Dhamma as initially taught by a Sammasambuddha. They might also lead others to enlightenment, but cannot teach the Dhamma in a time or world where it has been forgotten, because they depend upon a tradition that stretches back to a Sammasambuddha.
When the term Sāvakabuddha is used, it refers to a third type of Buddha, other than the Sammasambuddha and Paccekabuddha. The term Savakabuddha is used in Theravadin commentaries, and does not occur in the scriptures of the Pali Canon. The term regularly appears in Mahayana texts such as in Mahayana texts like Shantideva's Bodhisattvacharyavatara and in the Tibetan tradition. Śrāvaka (Pāli: Sāvaka) literally means "one who hears", i.e. a Buddhist who follows the path to enlightenment by means of hearing the instructions of others.
http://www.dhammawiki.com/index.php?title=Savaka-buddha" onclick="window.open(this.href);return false;
Thanissaro Bhikkhu speaks of this here:
In the early centuries after the Buddha's passing away, as Buddhism became a popular religion, the idea was formalized that there were three paths to awakening to choose from: the path to awakening as a disciple of a Buddha (
savaka); the path to awakening as a private Buddha (
pacceka-buddha), i.e., one who attained awakening on his own but was not able to teach the path of practice to others; and the path to awakening as a Rightly Self-awakened Buddha (
samma sambuddha). Each path was defined as consisting of perfections (paramī) of character, but there was a question as to what those perfections were and how the paths differed from one another. The Theravadins, for instance, specified ten perfections, and organized their Jataka collection so that it culminated in ten tales, each illustrating one of the perfections. The Sarvastivadins, on the other hand, specified six perfections, and organized their Jataka collection accordingly.
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http://www.accesstoinsight.org/lib/stud ... tions.html" onclick="window.open(this.href);return false;
with metta
Chris