1. The barrel or tube of a gun.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• fun barrel,
• vun barrel,
• bun barrel,
• hun barrel,
• yun barrel,
• tun barrel,
• gyn barrel,
• ghn barrel,
• gjn barrel,
• gin barrel,
• g8n barrel,
• g7n barrel,
• gub barrel,
• gum barrel,
• guj barrel,
• guh barrel,
• gun varrel,
• gun narrel,
• gun harrel,
• gun garrel

The adjective form of "gun barrel" is "barrelled" (or "barreled" in American English).

The plural form of the word "gun barrel" is "gun barrels".

The singular form of "gun barrel" is still "gun barrel".