playmate
"Playmate" is a warm, friendly word with a couple of closely related meanings. At its core, it describes someone you play or spend fun time with. It has a very innocent primary sense, most commonly used when talking about children, but it also has a well-known adult/media-related sense worth knowing about.
A playmate is simply a friend — usually a child — who you play with regularly. Think of the kids in your neighborhood or school who you ran around with, played games with, or spent time with just for fun. It is a very natural, affectionate word for a play companion.
everyday language, childhood · Modern, widely used