ʿĪd (festival) is that which arises in the qalb (the heart) from the tajalliyāt (divine manifestations) through the repetition of acts. (Iṣṭilāḥāt, 540)
ʿĪd is the portion of the tajallī (divine manifestation) that returns to the qalb, or, in any case, it is the time of tajallī. (Kāshānī, 134; Jāmiʿ, 91)