Why Was This 2,000-Year-Old Sling Bullet Inscribed With the Word 'Learn'?

From the Smithsonian:

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The artifact is the first sling bullet of its kind unearthed at the ancient city of Hippos, though archaeologists have found dozens of other examples without inscriptions at the site.

The city overlooking the Sea of Galilee was the site of several battles thousands of years ago.

Last year a team from the University of Haifa discovered this sling bullet made of lead and inscribed with the word "learn" in Greek.

The researchers think the word may be an abbreviated form of a phrase like "learn your lesson."

Sling bullets are almond-shaped projectiles, the earliest examples of which were made of stone or clay.

When this newly discovered artifact was made during the Hellenistic period, 

Attackers would place the bullet in a leather pouch before flinging it at the enemy.

Researchers have so far found 69 bullets at Hippos, most dating to the second century B.C.E.

The "learn" bullet measures just over an inch wide.

An analysis of the bullet suggests that it hit something.