Latchet

LATCHET (שְׂרֹֽוכְ ; ἱμάς, G2666). A leather strap or thong for tying on sandals (Gen 14:23; Isa 5:27 [RSV SANDAL-THONG]; Mark 1:7; Luke 3:16; John 1:27 [RSV THONG]).

International Standard Bible Encyclopedia (1915)

Leather thong used for tying on sandals (see Ge 14:23; Mr 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.