"Chest height" means the level or height at which your chest is when you measure or compare something. It refers to the height of an object or the position of an action in relation to your chest. Full definition
Hold one of the heavy dumbbells at chest height with both hands, elbows bent and drawn in tight to your sides and chest up the entire time. (mindbodygreen.com)
This means putting their food and water dishes at about chest height. (smartdogowners.com)
Snap your hips forward and swing the kettlebell up to chest height in one motion. (simplycantara.com)