'Day' in the Bible

Until the day is cool, and the shadows flee away, turn, my beloved, and be like a roe or a young hart on the mountains of Bether.

Go forth, you daughters of Zion, and see king Solomon, with the crown with which his mother has crowned him, in the day of his weddings, in the day of the gladness of his heart. Lover

Until the day is cool, and the shadows flee away, I will go to the mountain of myrrh, to the hill of frankincense.

We have a little sister. She has no breasts. What shall we do for our sister in the day when she is to be spoken for?