"To add a strap" means to attach a strip of material, usually with a buckle or fastener, to an object in order to make it easier to carry or wear on your body.
Sentences with «to add a strap»
And once I changed into the walking shoes later on, I also added the strap to carry the bag more easily around the city. (jerseyfashionista.com)
You could also make the basket for $ 6 plus glue and not add straps for a really cheap and chic basket! (aliceandlois.com)
Adding the straps adds an additional level of core recruitment and stability. (thebettyrocker.com)