In Jain time measurement, a palya (sometimes written as "palya" or "palyopama") is a very large unit of time, described metaphorically in Jain scriptures. The exact number of years in a palya is not fixed in terms of the modern calendar, as it is meant to convey an almost inconceivably long duration.

Traditional Jain description: A palya is defined as the time it would take to build a cube of lamb’s wool, with each side one yojana (about 8–9 miles) long, by placing a single strand of wool every hundred years.

Approximate calculation: Jain scholars have attempted to estimate a palya in terms of years, with common estimates stating that:

• 1 palya ≈ 10¹⁵ (one quadrillion) years

So, 1 palya or 1 palyopam is approximately 10¹⁵ years in Jain cosmology. This is a symbolic way to express incredibly vast periods of time, used to explain the duration of cycles in Jain cosmology.