Windowed thread

A paper-embedded security thread surfacing at regular intervals in a document and full visible when viewed in transmission.

Wire rim

A slight flange (protruded rim) on coins or medals caused by heavy striking pressure, often characteristic on proof coins.

Whizzing

The severe polishing of a coin in an attempt to improve its appearance and saleability to the uninformed.

Web printing process

Involves the feeding of a continuous roll (or web) of paper through the printing press. Web-fed offset lithography (as opposed to sheet-fed offset) is the predominant print process for tax stamps and other security labels.