Space and Time
The preposition "en" can most easily be translated to English as "in." However, this little word is much more complex than it seems. For starters, it can be used to communicate concepts of space and time. While the preposition "a" establishes a dynamic relation, the
preposition 'en' establishes static relationships.
"vivo en Madrid" (I live in Madrid), "en la calle" (in the street), "en el año 1961" (in the year 1961).
The initial element of the relationship created by the preposition is spatial, temporal, or abstract.
Abstract and Collective Concepts
The preposition "en" can also denote participation in abstract and collective concepts.
"soy ignorant en todo" (I am ignorant of everything), "valiente en la pelea" (brave in a fight), "hábil en engañar" (skilled in deception).
From this sense of participation in a larger abstract concept comes a set of related verbs that express thought and belief that function with the preposition:"creer en" (to believe in), "esperar en" (to wait/hope in), "confiar en" (to trust in), "dudar en" (to doubt in).
Note that the phrase "creer a mi hermano" means "to grant him credit in that which he says," while the phrase "creer en mi hermano" denotes a much more extensive belief in my brother which includes not only what he says, but also belief in his talents, his honesty, and all his other qualities. The preposition "en" functions the same way for the other verbs of thought that are have been listed.
Motion and Adverbial Phrases
The preposition "en" can often be combined with verbs of motion to vaguely express the end of the movement:
"caer en el agua" (to fall in the water), "entrar en la iglesía" (to enter the church).
The preposition "en" also has modal significance for numerous adverbial phrases:
"en serio" (seriously), "en broma" (jokingly), "en secreto" (secretly), "en general" (generally), "en particular" (in particular), "en absolute" (absolutely), etc.
Instrument and the Gerund
We can also use the preposition "en" to convey the instrument, means, or price of something.
"hablar en inglés" (to speak in English), "estar en pijama" (to be in pajamas), "viajar en avión" (to travel by airplane), "vender en 200 pesos" (to sell at 200 pesos).
Finally, the preposition "en" is also used with infinitives and the gerund to form adverbal phrases.
"Estoy caminando en el parque" (I am walking in the park), "Comemos en la cocina" (We eat in the kitchen).