Tap (tapas) in Jainism means disciplined self-control and austere practice done to purify the soul and progress toward liberation. It is not mere outward hardship; it is a focused effort to burn away karmic impurities by disciplined living, penance, and right conduct.

Why tapas is important in Jainism:

• Purification of the soul: Tapas helps burn karmas that bind the soul, bringing it closer to its natural state of peace and omniscience.
• Right intention and self-control: It cultivates inner restraint, humility, and non-attachment, reducing violence (himsa) in thoughts, words, and deeds.
• Spiritual progress: Through disciplined practice, a practitioner progresses on the path of purification (zadvipaka marg) toward Moksha (liberation).
• Complement to vows: Tapas enhances the effectiveness of the Jain vows (non-violence, truth, non-stealing, celibacy, and non-possessiveness) by strengthening resolve and inner discipline.
• Universal and personal scope: Tapas can be external (fasting, austere living) or internal (steadfastness of mind, deep reflection, penance, and controlled passions). Both forms aim at reducing karmic influx.

Different traditions on tapas:

• Digambaras: Often emphasize extreme ascetic practices and outward austerities as essential expressions of tapas, especially for monks.
• Śvetāmbaras: Highlight tapas as both outer disciplines and inner purification, stressing sincere inner purity and self-control, not just outward observances.

In short, tapas is the purposeful effort to discipline body and mind so that the soul can shed karma and realize its true nature.