'Hatband' definitions:

Definition of 'hatband'

From: WordNet
noun
A band around the crown of a hat just above the brim

Definition of 'Hatband'

From: GCIDE
  • Hatband \Hat"band`\ (h[a^]t"b[a^]nd`), n. A band round the crown of a hat; sometimes, a band of black cloth, crape, etc., worn as a badge of mourning. [1913 Webster]