In Jainism, Chaturmas refers to a four-month period during the rainy season (usually July to October), when Jain monks and nuns (sādhus and sādhvīs) stay in one place, refraining from travelling. This is done to observe greater spiritual practices and also to avoid unintentionally harming small living beings that proliferate during the rains.

The phrase "Prabhùnu antim chaturmas" refers to the last Chaturmas observed by a Tirthankara or a revered spiritual leader, most commonly referring to Lord Mahavira, the 24th Tirthankara. According to Jain tradition, Lord Mahavira's last Chaturmas was spent in the city of Pavapuri (in present-day Bihar), where he attained moksha (liberation) at the end of this period.

During his final Chaturmas, Mahavira delivered many important sermons and teachings to his disciples, which are recorded in the Jain Agamas. His passing (Nirvan or Moksha) is commemorated on Diwali by Jains, who celebrate it as the day of his liberation.

Thus, “Prabhùnu antim chaturmas” is a significant period in Jain history and spiritual practice, marking the culmination of the Tirthankara's earthly teachings and his attainment of moksha.