What is the Certified Pool/Spa OperatorÂ® Certification Program? A CPOÂ® Certification provides individuals with the basic knowledge, techniques, and skills of pool and spa operations. This training has helped protect millions of swimmers by reducing hazards at aquatic facilities.
A year is the orbital period of the Earth moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility.
Definition of annual. 1  1 : covering the period of a year annual rainfall annual income. 2  2 : occurring or happening every year or once a year : yearly an annual reunion an annual physical checkup. 3  3 : completing the life cycle in one growing season or single year annual plants.