A strap is a flexible flat material, that is applied to an item to combine, hold, reinforce or fasten it. Straps have been used to build no glue/no screws disassemblable furniture, but it is also common to use them for seats and sofas.

Synthetic straps can be made of nylon, polypropylene or polyester. The strength of the straps depends on the width and thickness. Nylon and polyester are stronger than polypropylene. Nylon is the most heavy duty type of straps, although it gets stretched more easily when wet and can lose its colors after long exposure to sunlight.