What is a javelin?

The javelin is a short, light spear thrown from the hand. It consisted of a metal point fixed at the end of a wooden shaft or handle. A strap was sometimes attached to aid in flinging the weapon with force and accuracy. It is an ancient weap­on. Saul, it will be remembered, strove to smite David to the wall with a javelin. The pilum which was thrown by Caesar's soldiers, and which caused the attacking Gauls so much inconvenience by pinning their overlapping shields together, was a weapon of this sort. The javelin was a favorite weapon of the Persian horseman and may well be regarded as the forerunner of the knight's lance. In the Middle Ages the javelin or boar spear was the trusty weapon of the hunt.

To be advised, thou know'st not what it is 
With javelin's point a churlish swine to gore. 
—Shakespeare, Venus and Adonis.