Latchet

From BibleEncyclopedia.Net

lach´et (שׂרוך, serōkh; ἱμάς, himás):

A thong (Acts 22:25), cord, or strap fastening the sandal on the foot (Isaiah 5:27; Luke 3:16).

Leather thong is used for tying on sandals (see Genesis 14:23; Mark 1:7 parallel). The stooping to untie the dusty shoe-latchet was esteemed by Orientals a service that was at once petty and defiling, and was usually assigned to menials.