I do not think 'cycle' is used anywhere in lore. It's just a logical conclusion about how the naming should work based on how everything is based around aetheric cycles.
You can see here that the information was in-game at some point in 1.0. You can see that there's a section called "Years", when the sections corresponding to days and months are called "Suns" and "Moons" respectively.
A member of my linkshell made a fancy guide about how Eorzea measures time. You can find it here. *shameless publicity*
You can see here that the information was in-game at some point in 1.0. You can see that there's a section called "Years", when the sections corresponding to days and months are called "Suns" and "Moons" respectively.
A member of my linkshell made a fancy guide about how Eorzea measures time. You can find it here. *shameless publicity*