From The Collaborative International Dictionary of English v.0.48 :
Latchet \Latch"et\, n. [OE. lachet, from an OF. dialect form of
F. lacet plaited string, lace dim. of lacs. See Lace.]
The string that fastens a shoe; a shoestring.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
latchet
n 1: a leather strap or thong used to attach a sandal or shoe to
the foot
From Easton's 1897 Bible Dictionary :
Latchet
a thong (Acts 22:25), cord, or strap fastening the sandal on the
foot (Isa. 5:27; Mark 1:7; Luke 3:16).