The term 'PERIOD OF DARKENING' can be summarized as a time of reduced light or darkness. The crossword solution for this term is EVE, which is the name of the first woman in the Bible. EVE was created by God to be Adam's companion and was the mother of all mankind. She is also known for her role in the Fall of Man, when she and Adam ate from the Tree of Knowledge of Good and Evil, resulting in their expulsion from the Garden of Eden.