In Jainism, 1 palyopam (palyopama / palya) is:

• A very, very huge unit of time, used only in Jain cosmology.
• It is not meant as a normal countable number of years like 100 or 1,000 years.

Traditional description (to show how long it is):

• Imagine a big pit (cube) of length, width and height 1 yojan (many kilometers).
• Fill it completely with very tiny hairs or particles.
• Now, every 100 years, remove only one tiny particle.
• The time taken to empty the whole pit like this is still less than 1 palyopam.

So, palyopam means an almost unimaginable, extremely long time period, used to explain ages of devas, cosmic cycles, etc., in Jain dharma.