Many thanks to all who replied on or off the list to my query on mudda/muddā. It seems fairly clear that the word as used in an astrological context is indeed an Arabic borrowing, although the compound mudda- or muddā-daśā looks a bit tautological ('period-period'). A meaning along the lines of 'modified, adapted' would have been more satisfying, as a muddā-daśā is in fact a modified sort of daśā; but usage isn't always as logical as one might like...
It is not uncommon to find redundant compounds in the Indian languages. In Hindi, pleonastic compounds such as tan-badan (body-body), dhan-daulat (wealth-wealth) and nātā-riṣta (relationship-relationship) are very commonly used. What is interesting about these compounds is that while one of the words in the compound is native, the other word is usually foreign (Perso-Arabic).
For a discussion on pleonastic compounds in Dravidian, you may refer to: Chandrasekaran, Periannan 2011 Pleonastic Compounding: An Ancient Dravidian Word Structure.
Electronic Journal of Vedic Studies 5: 1-57. (
http://www.laurasianacademy.com/pleonastic.pdf)
Given the abundant evidence of redundant compounds in India, I don't see anything unusual about the use of the compound muddā-daśā.
Regards,
Suresh.
Atlanta, GA.