1. materials placed beneath something else for support, protection, or cushioning

1. places something beneath or under another object
2. forms the basis or foundation for something

Examples

• The carpet installer used thick underlays to provide extra cushioning.
• She underlays the delicate fabric with tissue paper before cutting.
• The theory that underlays his research is well established.
• Foam underlays help reduce noise between floors.
• He carefully underlays each photograph with acid-free paper.
• A strong work ethic underlays all successful careers.
• The flooring company recommends moisture-resistant underlays for basements.