de·fer·ves·cence 
(dē′fər-vĕsəns)
(dē′fər-vĕsəns)n.
The abatement of a fever.
[From Latin dēfervēscēns, dēfervēscent-, present participle of dēfervēscere, to stop boiling, cool off : dē-, de- + fervēscere, to grow hot, inchoative of fervēre, to be hot, boil; see bhreu- in the Appendix of Indo-European roots.]
de′fer·vesce (-vĕs) v.
de′fer·vescent adj.