Maquila is a shorthand that people use. It comes from maquiladora, which is the zone in northern Mexico on the border with the United States. The technical term that you'll see in the development literature texts are export processing zones. In Spanish, it's zonas francas. Essentially, a maquila is a company that operates in a maquiladora or an export processing zone.
On May 21st, 2013. See this statement in context.