Jayan is not a standard or well-known term in Jain Dharmajna (Dharma). If you meant something like "Jayanti" (birth anniversary), then in Jainism we commonly refer to celebrations such as Mahavir Jayanti, which commemorates the birth of Mahavira, or other Tirthankara Jayantis.

If you were thinking of a specific term, name, or concept named “Jayan” in a Jain context, please share a bit more detail (where you saw it, the context), and I’ll clarify precisely based on authentic Jain sources.

You can read more about Jain festivals and Jayanti traditions here