'Cuerna de chivo" (KWEARNA dah CHEE-vo) is Spanish for "Ram's horn." This is a nickname for the AK-47 assault rifle, which has a distinctive curved magazine, bringing to mind the curved horns of a male mountain sheep. It is a fully-automatic
machine gun under U.S. law.
The AK-47 has many civilian copies ("clones") which are not
technically assault rifles, because they are semi-automatic, and are NOT
machine guns under U.S. law. They look very similar to actual AK-47's and to compound the confusion, are often called "AK's". And in Mexican Spanish, also called "cuerna de chivos."