Embruon is a Greek word. It appears in Homer's Odyssey meaning the young of a lamb or a goat. Zygote means yoked. Zygote embryon literally "Yoked goat" or scape goat. Alternatively, a sacrificial lamb.
Christians believe that Jesus crucifixion was the Paschal sacrifice. A pagan could have another type of scapegoat or sacrificial lamb. If you don't go to Church, or believe in Jesus, something else could be turned into a sacrifice.