Definition from Wiktionary, the free dictionary
fretty (not comparable)
- (heraldry) Covered with a lattice-like pattern of diagonally interlaced bendlets and bendlets sinister.
- The coats of various noble British families were originally fretty, but later 'simplified' to a single fret
- In heraldic descriptions, the term is used between the color of the field and the color (most often a metal) of the bendlets to specify the tinctures of the fretwork.