The Collaborative International Dictionary
Effervescency
Effervescence \Ef`fer*ves"cence\, Effervescency \Ef`fer*ves"cen*cy\, n. [Cf. F. effervescence.] A kind of natural ebullition; that commotion of a fluid which takes place when some part of the mass flies off in a gaseous form, producing innumerable small bubbles; as, the effervescence of a carbonate with citric acid.
Wiktionary
effervescency
n. (context archaic English) effervescence