Bodhisattvas (bodhisattas in Pali) are "Buddhas to be". The Buddha, before his enlightenment, was a bodhisatta. A bodhisattva is one who has vowed to help all sentient beings attain enlightenment.

In much of general usage, the phrase often implies that the bodhisattva has attained a certain level of progress on the path. So, usually you wouldn't call your uncle a bodhisattva, even if he has taken the Bodhisattva vows, unless you think he has made such extraordinary progress that people think he is enightened, or at least embodying most of the characteristics of an enlightened person .

In Mahayana Buddhism, bodhisattvas are of great importance. Often they are celestial beings, such as Kwan Yin.