This form uses metal thread instead of the usual silk or rayon.

Security thread: A straight metal thread is embedded in the note.

The metal thread looks like a dotted line when put on a surface but solid when held up to light.

I can't explain it, but you had a metal thread in the embroidery, and it melted.

One was opened to reveal a coil of metal thread.

A metal thread was added to the notes in 1957 for greater security.

Goldwork is the art of embroidery using metal threads.

Made of the finest wool, silk, and metal thread.

Some American currency has a polyester; some British pounds have a metal thread.

A metal thread woven through or a flash of sequins adds a special glow for evening.