An assembly plant in Mexico (near the United States border); parts are shipped into Mexico and the finished product is shipped back across the border WordNet 3.0 & Open English WordNet

A maquiladora, or maquila, is a word that refers to factories that are largely duty free and tariff-free. Wikipedia

An assembly plant in Mexico owned by a company from the United States or another foreign country, using cheap local labour and imported components, and which then exports its products to the company's country of origin; also (by extension) similar factories in other countries. Wiktionary

An assembly plant in Mexico near the border with the United States. Wiktionary (translation)