'Locket' definitions:

Definition of 'locket'

noun

A small ornamental case; usually contains a picture or a lock of hair and is worn on a necklace

From: GCIDE

Locket \Lock"et\, n. [F. loquet latch, dim. of OF. loc latch, lock; of German origin. See Lock a fastening.] [1913 Webster]
1. A small lock; a catch or spring to fasten a necklace or other ornament. [1913 Webster]
2. A little case for holding a miniature picture or lock of hair, usually suspended from a necklace or watch chain. [1913 Webster]