A spiculum is a late Roman spear that replaced the pilum at around AD 250 as the infantryman's main throwing javelin. Scholars suppose that it could have resulted from the gradual combination of the pilum and two German spears called an Angon and a Bebra. As more and more Germans joined the Roman army their culture and traditions became a driving force for change. The spiculum is better than the old Pilum for retention in the hand, used as a thrusting spear, but still maintaining some of the former weapons penertrative power when thrown.

Vegetius mentions the spiculum in his military manual, but some scholars maintain that the spiculum was simply a different name for the pilum. Whatever the case, most historians accept that the spiculum evolved from the earlier javelins used by the Roman army

The main difference between the spiculum and the pilum was the length of the thin point. The spiculum tended to have a much shorter iron point. Thus, the spiculum was significantly shorter than its ancestor, perhaps 190 cms long. The spiculum had a medium iron shank attached to the head. Its exact design is not fully known as there are many variants. The spiculum fell out of favour with the Roman army some time after AD 400.