What was the "Seven Foot Pilum" in the Roman arsenal of weapons?

The Roman "Seven Foot Pilum" was a javelin.

The pilum was the characteristic throwing weapon of the Roman legionary. It consisted of a wooden shaft joined to a long iron shank and pointed head, giving it a length of roughly seven feet in some descriptions. Unlike a simple spear intended mainly for close combat, the pilum was designed to be thrown before soldiers closed with the enemy.

Its heavy construction gave the weapon considerable penetrating power. Some pila were made with a softer iron shank that could bend after impact, making a shield awkward or unusable and preventing the enemy from throwing the weapon back. The pilum therefore helped disrupt formations as well as wound opponents.

The answer is sometimes confused with "spear," since both are pole weapons. In standard historical classification, however, the pilum is a specialized Roman javelin. Legionaries commonly carried pila alongside the gladius, their short sword used in hand-to-hand fighting.