Term used to refer to a foreigner in a latin-american country. Can be derogatory or not, it usually is derogatory when an article is used before it (Este Gringo.) Believed to have originated from the chant "Green, Go" shouted at US soldiers during the Mexican-American war, It actually originates from the Spanish 'Griego' meaning greek. In spanish, the phrase "Hablar en Griego" or 'to speak in greek' means the same as the english "It's all greek to me." The word Gringo is an evolution of griego, which was used to describe any foreigner that had an accent that prevented them from speaking spanish; particularly the Irish.
"The Gringos are coming!"