Age
From MYSTlore
An Age (sev[?] (sev)) is a "world" (technically, a universe). According to the D'ni belief, Ages are leaves of the Terokh Jeruth, they are infinite in number and were all created by Yahvo the Maker.
Ages were described through the Art in a descriptive book. The D'ni civilization (and the Ronay before them) gave prominent place to a Guild of Writers who were trained to become masters of the Art.
[edit] Terminology
In practical speech, it is a usual custom to consider only the interesting, visible or explorable portion of a world of a universe as an Age, while this is inconsistent to the proper definition of an Age, which means a whole universe.
For example the Age of Myst is properly the whole universe where the planet with the Myst Island belongs; however we can also claim "The Age of Myst is an island" since this specific island is the only place of interest of that Age, and the Age itself was written in order to host that island.
Therefore, phrases such as "Atrus's sons murdered all people of Mechanical," or "Spire was an Age over a green planet's surface," in no way refer to the whole universe, but to the certain part of the Age the explorer visits.
