संस्‍कृतशब्‍दकोशः

Monier–Williams

आतप् — {ā-√tap} {-tápati} (Impv. {-tapatu}##{ā-tápat} and {ā-tápas} ss.vv.) to radiate heat : Pass. (p. {-tapyamāna}) to suffer pain, be afflicted##(with {tapas}) to inflict (austerities) upon one's self