Proper noun
X-Acto
A utility knife, usually with a short, sharp, disposable blade mounted on a pen-like body, usually for crafts and hobbies; an X-Acto knife.
Fixed blade utility knife For Fixed-blade X-Acto knife for handicrafts and model making. Source: Internet
In Portugal and Canada they are also known as X-Acto (yet another genericised trademark ). Source: Internet
One of the most popular types of workplace utility knife is the retractable or folding utility knife (also known as a Stanley knife, box cutter, X-Acto knife, or by various other names). Source: Internet