For a physical location:
* atrás: This is the most common word for "back" in the sense of behind something or someone.
* Example: "El libro está atrás de la mesa." (The book is behind the table.)
* detrás de: This is another option for "behind," often used in a more formal context.
* Example: "Se escondió detrás de la puerta." (He hid behind the door.)
* la espalda: This means "the back" as in the back of the body.
* Example: "Me duele la espalda." (My back hurts.)
For returning to a previous place:
* volver: This means "to return" or "to go back."
* Example: "Volví a casa." (I went back home.)
For going back in time:
* retroceder: This means "to go back" in the sense of time.
* Example: "Retrocedamos en el tiempo." (Let's go back in time.)
For a reaction:
* responder: This means "to respond" or "to answer back."
* Example: "Le respondió con una sonrisa." (He answered her with a smile.)
For the back of something:
* el dorso: This means "the back" of something like a hand or a book.
* Example: "Escribió su nombre en el dorso de la carta." (He wrote his name on the back of the letter.)
So, the best translation for "back" in Spanish depends on the specific situation.