*climacteric*

n. 1. A period in human life in which some great change is supposed to take place in the constitution. The critical periods are thought by some to be the years produced by multiplying 7 into the odd numbers 3, 5, 7, and 9; to which others add the 81st year. [ 1913 Webster ]

2. Any critical period. [ 1913 Webster ]

It is your lot, as it was mine, to live during one of the grand climacterics of the world. Southey. [ 1913 Webster ]