Dictionary Definition:
Usumā (f.) [the diaeretic form of Sk. uṣman, of which the direct equivalent is P. usmā (q. v.)] heat J i.31 (= uṇha iii.55), 243; ii.433; Vism 172 (usuma -- vaṭṭi -- sadisa); DA i.186; DhA i.225; ii.20.