A playgroup could be a group of very small children who are learning how to socialize and play together with caretakers in charge. This is not a common term to me. Nursery school is a childcare facility that would be licensed and have trained teachers that provide structured activities for children who are 2-5 years old. A Kindergarten is a licensed school or pre-school that provides hand-eye coordination, basic counting, familiarization of the alphabet and sounds letters represent, vocabulary building and general instruction for following directions, manners, and starts the foundation for further educational concepts.

A playgroup or pre-school group is a registered childcare facility that offers sessional care - usually 2-3 hours - for children between the ages of 3-5 years. Nursery is a daycare facility for preschool-age children. The term kindergarten is used around the world to describe a variety of different institutions that have been developed for children ranging from the ages of two to seven, depending on the country concerned..

A nursery is for the smallest children when parents need them to be taken care of. It is not part of a school (for children). It is likely a business, but may also be at a college, church or business. A kindergarten is the first "school" before 1st grade. It is for 4-5 years old. A playground may be at a school or park or church or home or business. It is an area set aside for playing and usually has equipment such as swings or slides or swinging bars to nock kids teeth out.