Calendarial is a coined adjective from a word everyone knows, which is the right way to build a software brand. The root does the explaining and the invented ending makes it ownable.
On the .net there’s a specific fit. Calendar interoperability is a genuine technical problem handled by open standards, and the extension reads as network and infrastructure rather than as a consumer product. A calendaring API, a sync service, a federation protocol, or a developer tool would all sit naturally here.
The consumer reading works too: a scheduling app, a booking product, or an events platform. Scheduling is a crowded category where every descriptive name went years ago, so a coined word that still says “calendar” in its first five letters is a real find.
Eleven letters, entirely phonetic, no hyphen, no silent characters, and it survives being spelled out over a phone call.
The name is listed for sale. Offers welcome.