In fencing, a practice sword is typically called a "foil." The foil is one of the three weapons used in modern Olympic-style fencing, along with the épée and sabre.

The foil is a flexible weapon with a rectangular cross-section blade that tapers to a point. It is primarily a thrusting weapon, and touches are scored only with the tip. Foil fencing emphasizes precision, control, and technique, and the rules of the sport dictate specific target areas, such as the torso (including the back), excluding the arms and head.

Foil blades are designed to be lightweight and flexible to facilitate quick and accurate movements. They are constructed with a blunt tip and a button or rubber tip that covers the point to ensure safety during practice and competition.

It's worth noting that while the term "foil" specifically refers to the practice sword used in the sport of fencing, in broader historical contexts, "practice sword" can refer to various training weapons used in different martial arts disciplines, including HEMA (Historical European Martial Arts) and other forms of swordsmanship.