Metro vs. subte vs. subterráneo
The Spanish language, depending on the country and region, may use different words to refer to the same concept. The terms 'metro', 'subte' and 'subterráneo' are all used to describe a subway or underground transport system, but their usage varies primarily by location.
Metro
This term, borrowed from other languages like English and French, is broadly used in many Spanish-speaking locations to describe a rapid transit system found in urban areas.
Tomo el metro todos los días para ir al trabajo.
(I take the metro every day to go to work.)
El metro de Madrid es muy extenso y conecta toda la ciudad.
(The Madrid metro is very extensive and connects the entire city.)
¿Sabes si el metro funciona las 24 horas?
(Do you know if the metro operates 24 hours?)
Subte
This is a term that's predominantly used in Argentina (specifically Buenos Aires) and Uruguay for their underground train services. It's an abbreviation of 'subterráneo'.
Voy a tomar el subte para evitar el tráfico.
(I'm going to take the subway to avoid traffic.)
El subte de Buenos Aires es uno de los más antiguos del mundo.
(The Buenos Aires subway is one of the oldest in the world.)
¿Cuánto cuesta el boleto de subte?
(How much does the subway ticket cost?)
Subterráneo
Literally translating to 'underground', this word also refers to an underground railway system. However, it's not as commonly used as 'metro' when referring to public transportation.
Preferiría tomar el subterráneo que el autobús por cuestiones de tiempo.
(I would prefer to take the underground than the bus due to time constraints.)
El sistema subterráneo de transporte es una solución para reducir la congestión en la superficie.
(The underground transport system is a solution to reduce surface congestion.)
Construir un subterráneo puede ser costoso pero beneficia a la ciudad a largo plazo.
(Building an underground can be expensive but benefits the city in the long term.)
Summary
'Metro', 'subte' and 'subterráneo' all refer to an underground transit system in Spanish-speaking countries, with 'metro' being more globally understood, 'subte' being frequently used in Argentina and Uruguay, and 'subterráneo' being a strictly literal translation of 'underground'. The context and location play a significant role in which term might be used.