This is the 817th most frequent Spanish word.
electrónico
Relating to or involving electronics.
Here, 'electrónico' is used as an adjective to describe 'correo,' indicating that the form of the correspondence is electronic.
El correo electrónico es una herramienta común.
The email is a common tool.
In this sentence, 'electrónico' describes 'dispositivo,' referring to a device that operates based on electronic principles.
El dispositivo electrónico facilita nuestras vidas.
The electronic device makes our lives easier.
'Electrónico' modifies 'libro,' highlighting the nature of the book being in a digital, electronic format.