adjective
double-sided, two-sided
“Est-ce que le cours est en format recto-verso?” — Is the course material in double-sided format?
From recto (“the right page of a left to right reading language script”) and verso (“the left page of a left to right reading language script”).
adverb
in double-sided, as double-sided
“On n'imprime pas les partitions de musique recto-verso.” — One doesn't print music sheets as double-sided.
From recto (“the right page of a left to right reading language script”) and verso (“the left page of a left to right reading language script”).