Fretwork
Etymology
From "fret," an ornamental pattern of interlaced lines, plus "work." The "fret" here likely comes from Old French "frete" (trellis, interlaced work); it is a separate thread from both the guitar "fret" and "fret" meaning to worry, whose origins are tangled and debated.
noun · /FRET-wurk/
Ornamental openwork or carved interlacing patterns, often in wood or stone.
What it names
Those lacy, cut-through decorative panels — on Victorian porches, screens, and furniture.
Example
Sunlight fell through the carved fretwork and scattered lace-like shadows on the floor.
Related idea
Fretwork is the decorative pattern itself; filigree is its finer, jeweler’s cousin — delicate twisted wire worked into metal ornament.