Definitions

1. noun

The strap or band that passes over the shoulders and across the back, especially of a pack or a harness.

“He adjusted the backstrap on his backpack to get a comfortable fit.”

2. verb

To support or secure something, typically a pack or load, with a strap that passes over the shoulders and across the back.

“She had to backstrap her heavy suitcase onto the plane’s luggage cart.”