Rape is non-consensual sexual activity. If a man or a woman does not give consent, then it is rape. (Same if they are unable to give consent, like drunk or passed out)
In the annunciation god just announces to Mary that she is pregnant.
26 In the sixth month of Elizabeth’s pregnancy, God sent the angel Gabriel to Nazareth, a town in Galilee, 27 to a virgin pledged to be married to a man named Joseph, a descendant of David. The virgin’s name was Mary. 28 The angel went to her and said, “Greetings, you who are highly favored! The Lord is with you.”
29 Mary was greatly troubled at his words and wondered what kind of greeting this might be. 30 But the angel said to her, “Do not be afraid, Mary, you have found favor with God. 31 You will conceive and give birth to a son, and you are to call him Jesus. 32 He will be great and will be called the Son of the Most High. The Lord God will give him the throne of his father David, 33 and he will reign over the house of Jacob forever; his kingdom will never end.”
34 “How will this be,” Mary asked the angel, “since I am a virgin?”
35 The angel answered, “The Holy Spirit will come on you, and the power of the Most High will overshadow you. So the holy one to be born will be called [a] the Son of God.
There was no asking Mary “Hey, do you consent to this?”, she had no choice, god just knocked her up and told her afterwards.
I can foresee people saying “Oh, but she was fine with it! How can it be rape if she’s ok with it?” Simple. Did she consent to being impregnated before she was impregnated? No. Then it’s rape. It does not matter if she is ok with it afterwards. I know a girl here at college that was drugged and raped by a guy she liked. She refused to press charges afterwards because she thought he was “a nice guy” but that does not change the fact that she was raped. Just like Mary.