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 era. 1  1a : a fixed point in time from which a series of years is reckonedb : a memorable or important date or event; especially : one that begins a new period in the history of a person or thing. 2  2 : a system of chronological notation computed from a given date as basis.