middle age: the time of life between youth and old age (e.g., between 40 and 60 years of age)
time of life: a period of time during which a person is normally in a particular life state
ijtihad: the endeavor of a Moslem scholar to derive a rule of divine law from the Koran and Hadith without relying on the views of other scholars; by the end of the 10th century theologians decided that debate on such matters would be closed and Muslim theology and law were frozen