Ovulation is when an egg is released from the ovary into the fallopian tube, where it awaits the possibility of fertilization. Normally, one egg is released during a cycle, however, multiple ovulation is possible, and occurs when two or more eggs are released during one cycle.
According to American Pregnancy, normal ovulation is when one egg is released into the fallopian tubes to be fertilized or discarded. Every woman's body is different, and ovulation can occur at different times of the month, depending on that particular woman's cycle. Multiple ovulation is not as common, but possible. This happens when two or more eggs are released during one cycle and is the cause of the birth of twins.