The phrase "a security thread" is correct and usable in written English.
It can be used when referring to a feature in banknotes or documents that provides a level of security against counterfeiting.
Example: "The new banknotes include a security thread that changes color when viewed from different angles."
Alternatives: "anti-counterfeit thread" or "security strip".
IN 1996, the Bureau of Engraving and Printing began to distribute paper currency that incorporated anticounterfeiting measures like color-shifting ink, microprinting and a security thread woven into the paper.
Almost everything about the new design was aimed at frustrating potential counterfeiters, including a security thread embedded in the paper, a watermark featuring a shadow portrait of the figure on the bill and new "microprinting," tiny lettering that is hard to imitate.
Here's another tip that you might not have recognized: every denomination higher than the $1 has a security thread running vertically through the note.
A security thread, embedded in the banknote paper.
A security thread, The security thread is embedded in the banknote paper.
These combine with traditional security features, such as a portrait watermark and an embedded security thread that glows pink under ultraviolet light.
Other features, however, will make copying far more difficult than it was: the new bill has enhanced security devices including a watermark, security thread and special inks.Thomas Ferguson, director of the Treasury's bureau of engraving and printing, says that keeping counterfeits at bay has as much to do with strict law enforcement and public co-operation as it does with high technology.
For enhanced security, there is a plastic security thread embedded in the paper, ink that changes colors when it is tilted in the light (from copper to green instead of the old green to black) and more microprinting, the tiny letters that are difficult to reproduce.
In 2008 the $5 got a redesign with the portrait watermark replaced by a "5" and the security thread being moved from left of the portrait to the right.
The behavior that he wants to change includes stuffing the $20 bill, the most frequently counterfeited in the United States, into a pocket or cash register before checking its authenticity by, say, holding it up to a light or feeling for the security thread.
Security Thread: When the note is held against the light, the security thread appears as a dark line.
