The phrase "sturdy frame" refers to a strong and solid structure, such as a person's body, a piece of furniture, or a building, that is well-built and unlikely to collapse or break easily. Full definition
-- Quality: A top - notch suspension system with adjustable straps provides a particularly smooth ride, and a lightweight but sturdy frame makes folding and storage easy. (babygearsguide.com)
The fabric removes from the steel, sturdy frame for super easy washing right in your machine. (themamaneeds.com)
The lightweight, sturdy frame folds up and out easily, so it's quick to assemble and put away. (tinyfry.com)