（1） To learn， to study， to practice--i.e.， to learn something by repetition. Habituation. （2） To get accustomed to; customs， habits. （3） To pile up， to add up. （4） The original meaning of this character is for a baby bird to learn how to fly by repeated attempts. （Buddhism） （1） An abbreviation for 习气， 'habit energies.' Traces， or remains of defilement. （2） A Chinese translation of samudaya， the second of the four noble truths， more commonly written in Chinese as 集. （3） Mistaken habituated nature.