This is the 5491st most frequent Spanish word.
paralelo
Parallel.
Here, 'paralelo' is used as an adjective to describe the positional relationship between the trains and the tracks.
Los trenes viajan en paralelo por las vías.
The trains travel in parallel along the tracks.
In this case, 'paralelas' functions as an adjective describing the type of lines being discussed, specifically in the context of geometry.
Los estudiantes compararon líneas paralelas en geometría.
The students compared parallel lines in geometry.
Here, 'en paralelo' is used as an adverbial phrase to describe the simultaneous occurrence of two events.