shoulder strap
noun [ C ] uk/ˈʃəʊl.də ˌstræp/ us/ˈʃoʊl.dɚ ˌstræp/
（包或衣服的）肩带，背带
a narrow strip of material on a bag or a piece of clothing that hangs over the wearer's shoulder and holds the bag or clothing in position
See also: strap noun