Bharatvarshji,
Since the days are named after the 5 planets, the Sun and Moon, probably their synonyms are derived too based upon the qualities of those nakshatras.
Sunday is Ravivaar - and Ravi is Aditya - doer of the beginning - probably therefore Adivaar. In Hindi too 'itvaar' (an apabransha of Adivaar) is still more popular for Sunday, as compared to Ravivaar.
Likewise for Thursday, Vrihaspativaar is the name, from which Guruvaar came - Vrihaspati is the Sura-Guru. I am not sure where did Veevaar come from, though.
In same way, Angarakavaar can probably be explained for Mangalvaar.
Not sure how it relates to Bhaumvaar...
Since the days are named after the 5 planets, the Sun and Moon, probably their synonyms are derived too based upon the qualities of those nakshatras.
Sunday is Ravivaar - and Ravi is Aditya - doer of the beginning - probably therefore Adivaar. In Hindi too 'itvaar' (an apabransha of Adivaar) is still more popular for Sunday, as compared to Ravivaar.
Likewise for Thursday, Vrihaspativaar is the name, from which Guruvaar came - Vrihaspati is the Sura-Guru. I am not sure where did Veevaar come from, though.
In same way, Angarakavaar can probably be explained for Mangalvaar.
Not sure how it relates to Bhaumvaar...