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.
decade. 1  a period of ten years: the three decades from 1776 to 1806. 2  a period of ten years beginning with a year whose last digit is zero: the decade of the 1980s. 3  a group, set, or series of ten.