We have a big umbrella that we take to the beach to protect us from the Florida sun. Actually, it is big enough to overshadow a number of people. Overshadow is our word for today.
Mary was a virgin, yet the angel Gabriel told her that she was going to conceive in her womb and bear a son. When Mary asked, “How can this be?” in Luke 1:35 the angel said, “The Holy Spirit will come upon you, and the power of the Highest will overshadow you; therefore, also, that Holy One who is to be born will be called the Son of God.” In other words, this would be a special work of God whereby the Holy Spirit would overshadow her.
The word overshadow is a word that means to cast a shadow. Then, a prefixed preposition is added to this word which means over or upon. So, the idea really is to cast a shadow over or upon something.
Well, the angel was telling Mary that the power of God would become a protective shield over her so that nothing would contaminate the process. The baby in her womb was going to be holy, which is like saying that it would be absolutely pure, protected from any intrusion of sin and evil. So, like a beach umbrella that shields you from the harmful rays of the sun, God would cast His shadow over Mary to shield her from any harmful influence. God would created a protective hood over her to ensure a sterilized environment, not just to eliminate the presence of germs, but to make sure that no sin would contaminate the seed. The baby would be holy and the power of the Highest would overshadow her to make sure of that.
Now you know the real meaning of the word.
The virgin birth was a delicate process, and God made sure it was done right.