Webster's Revised Unabridged Dictionary · 1913

Defervescence

Defervescence , noun

[Latin defervescere to grow cool.]

1.
A subsiding from a state of ebullition; loss of heat; lukewarmness.
A defervescency in holy actions. — Jer. Taylor
2.
(Medicine) The subsidence of a febrile process; as, the stage of defervescence in pneumonia.

Also: Defervescency