:::::Quite so. The terms are well established at least in Islamic and Indian studies, whether or not it seems to make logical sense. The term isn't really all that sensible in the European sense either; there is no firm date when Antiquity ended and the Middle Ages began, or when the Middle Ages ended and the modern era began. "Medieval Islam" is generally used as in Europe. I have a book on my shelf, J. J. Saunders History of Medieval Islam, which covers roughly the era from the time of Muhammad to the fall of Baghdad in the 13th century. Gustave E. von Grunebaum's Medieval Islam discusses the period between the rise of Islam and the "close of the Middle Ages". What constitutes "Medieval India" is also much discussed. /