(the crossed nimb). The Cross symbolizes the suffering and resurrection of Christ; having passed through crucifixion and death on the Cross, Jesus Christ rose and saved all people from sin and death. All symbols ultimately mean that Jesus Christ is The Existing One or the eternal and true God — the Savior. From the combination of these symbols comes the name of this icon of Jesus Christ: the image of the Savior or “Spas.”
Next to the nimb of the Virgin Mary is the inscription ancient Greek Μ ҃ Ρ Θ ҃ Υ. This means Μήτηρ Θεού — “Mother of God” or “Theotokos.”
In Buddhism
The earliest depictions of the nimb appear in Buddhist art of the 1st–2nd centuries due to Hellenistic influence (Gandhara). The rulers of the Kushan Empire depicted themselves with nimbuses on coins. The nimb sometimes signifies spiritual power, as opposed to secular authority represented by a crown. The nimb can be blue, yellow, or rainbow-colored. In Buddhism, the red halo of the Buddha symbolizes dynamic solar activity.
In Hinduism
The depiction of the nimb in Indian art dates back to the second half of the second millennium BCE. In India, the halo around the head was called Prabhamandala or Siras-cakra, and the halo around the body was called Prabhavali.”
I also found something interesting about the nimb specifically in the form of an eight-pointed star.
“It has a deep and rich symbolic meaning in Christian iconography.
1. New Testament and Resurrection.
The eight sides can symbolize renewal and resurrection in Christian tradition, as the eighth day was considered the day of new creation after the Sabbath, the seventh day. This emphasizes eternal life and the new covenant with God.
2. Universe and complete cycle of time.
The eight directions can represent the completeness and all-encompassing aspect of the Universe, symbolizing harmony and cosmic order.