The phrase "height limit" refers to a maximum acceptable or allowed height for something. It sets a boundary that should not be exceeded in terms of how tall a building, object, or structure can be built. Full definition
It has a forward facing weight capacity of 20 to 65 lbs, and a forward facing height limit of 49 inches. (babieslounge.com)
We'll give you the highest height limit for each cot in feet. (geekwrapped.com)
You should also check the manufacturer's rear - facing height limit to be sure baby is not too tall to safely stay rear - facing to the weight limit. (thespruce.com)