Gringo (feminine, gringa) is a Spanish and Portuguese word used in Latin America to denote foreign non-native speakers of Spanish (regardless of race), especially English-speakers from the British Isles, and Americans, Canadians, Australians, and New Zealanders, as well as some other Latin Americans.
Hispanophones disagree whether or not gringo is derogatory. The American Heritage Dictionary entry classifies gringo as "offensive slang", "usually disparaging", and "often disparaging". The usages of gringo sometimes are derogatory, paternalistic, and condescendingly endearing, especially when a foreigner condescends to the people and culture he or she is visiting. The enunciation of the word communicates connotation, insult or not. Like many derogatory terms, gringo has been co-opted; drummer Randy Ebright, of the band Molotov, dubbed himself El Gringo Loco (The Crazy Anglo).
These explanations are unlikely, since the U.S. Army did not use green uniforms until the 1940s, but rather blue ones, and after that brown (early 20th century including World War I).
Another assertion maintains that one of two songs – either "Green Grow the Lilacs" or "O Green Grow the Rushes" – was popular at the time and that Mexicans heard the invading U.S. troops singing "Green grow..." and contracted this into gringo.
Another hypothesis maintains that the U.S. troops, during the Mexican-US war were looking for the green grass (Marihuana) which may be misunderstood by the Mexicans as "gringo"
However, there is ample evidence that the use of the word predates the Mexican-American War.
In the Dominican Republic it is said that the term was a mispronunciation of the words "green gold", referring to the green color of U.S. currency, as well as the corruption of the exclamation: "green go!", said to have voiced local opposition within the volatile context of both U.S. military interventions to the Island. Another interpretation makes a generalized character judgment of U.S. citizens: "they see 'green' (money) and they 'go' (after it)".
According to the Catalan etymologist Joan Coromines, gringo is derived from griego (Spanish for "Greek"), the archetypal term for an unintelligible language (a usage found also in the Shakespearean "it was Greek to me" and its derivative "It's all Greek to me"). From referring simply to language, it was extended to people speaking foreign tongues and to their physical features — similar to the development of the ancient Greek word βάρβαρος (bárbaros), "barbarian". Still, scholars are not in agreement about the correct origin of this word.
In Brazil, the meaning and use of gringo differs significantly from the Spanish-speaking Latin American countries.
Etymologically, the word is documentedly not native to European Portuguese language and is actually borrowed from Spanish since the 19th century at least. Thus the Greek reference is reinforced there as the word "grego" for Greek in Portuguese (without the "i") would not have given "gringo". Also in Brazilian or even Portuguese popular culture, someone unintelligible is traditionaly said to speak Greek (sometimes German or, much more recently, Chinese).
This is also reflected in that the word usage is not naturally widespread and only generally in regions exposed to tourism like Rio de Janeiro. There, the word means basically any foreigner, North American, European or even Latin American, though generally applying more to any English-speaking person and not necessarily based on race or skin color but rather on attitude and clothing. The word for fair skinned and blond people would be rather "Alemão" (i.e., German).
In the 1950s, the blue Fifty Mexican peso bill was called an ojo de gringa ("gringa's eye").