‘Practice makes perfect’ as the saying goes. Practice is nothing but repetition of effort to achieve perfection. The word is used in a technical sense in the Yoga system of Patañjali. Repetition of effort put forth to keep the modifications of mind, called vṛttis, suppressed, is called abhyāsa. This abhyāsa when kept up over a long period, but in unbroken continuity, and with devoted faith, will become firmly established leading to yogic states (vide Yogasūtras 1.12, 13, 14).
In Sanskrit grammar, the word is used to indicate the first part of the duplicated verbal root (vide Aṣṭādhyāyī of Pāṇini 6.1.4).