Noun
the time of life between 40 and 50
Source: WordNetI'm looking forward to being old, to be able to accept what I am and become self-sufficient. Mid-forties is a good age and it's not too far away. Stella Vine
He did not begin serious work in economics until his mid-forties. Source: Internet
He spent all his career in Florence until his mid-forties, when he travelled to work in various cities, as far south as Rome. Source: Internet