Minecraft wiki entry for Barrel, associated text: By default, the GUI of a barrel is labeled "Barrel". A barrel's GUI label can be changed by naming the barrel in an anvil before placing it or by using the /data command‌[Java Edition only] (for example, to label a chest at (0,64,0) as "Bonus Barrel!", use /data merge block 0 64 0 {CustomName:'"Bonus Barrel!"'}).