1. The origin of the word bāj is doubtful. There are two probable derivations. First, from vac “word, speech.” This derivation seems meaningful in some of the uses of the term. The other from Persian wāj, used in the sense of “tribute, tax” This derivation makes senses when the word bāj is used for the after-death ritual, and serves the sense of repaying debts to the ancestors.
2. In contemporary Parsi usage, the word bāj is used for several purposes:
i) Prayers which precede and follow an action, in other words ‘frame’ an action. It is generally a daily act like eating, drinking, bathing or answering the call of nature. Once the initial portion of the bāj preceding the action has been recited, silence has to be maintained till the bāj is concluded by the recitation of the concluding portion. The initial portion of the bāj is referred to as ‘taking the bāj’ (G. bāj levi, bāj dharvi) and the concluding portion as ‘leaving the bāj’ (G. bāj chhodvi, bāj mukvi). These bāj are found in the Khordeh Avesta. These bāj protects the person when the act is being performed, as the act somehow breaches some boundary of religious appropriateness.
ii) The term bāj is also used for the prayer formulae before and after prayers like the Nyash, Yasht and certain Nirangs. These prayer formulae have a common invocation at the beginning and the end.
iii) In modern Parsi parlance, the term ‘praying in bāj’ refers to a particular suppressed tone of prayer, especially used to recite Pazand passage/s occurring between two Avestan texts.
iv) A Zoroastrian is not supposed to talk whilst reciting prayers. However, if he has to perforce talk, he is supposed to speak ‘silently’ or ‘inarticulately’ in a suppressed tone by pursing the lips together. Such a mode of conversation is referred to as ‘speaking in bāj.’
v) The Bāj-dharnā ritual is also referred by the shortened name bāj. In the set of 4 after death rituals, this ritual is referred to as just the bāj. The other 3 are Afringan, Farokshi and Stum.
vi) Since the Bāj-dharnā ritual is generally performed in memory of departed ones, the days of monthly and annual commemorations are also referred to as ‘the person’s bāj.’
vii) One more unique use of the term bāj is in the short prayer Sarosh Bāj. Though this prayer is not a bāj in any sense of the word discussed above, and is a normal basic prayer, still it is called a bāj.
3. Thus, there are various understandings and connotations in which the word bāj is used by the Parsis.