v. i. [ imp. & p. p. Effervesced p. pr. & vb. n. Effervescing ] [ L. effervescere; ex + fervescere to begin boiling, incho., fr. fervere to boil. See Fervent. ] 1. To be in a state of natural ebullition; to bubble and hiss, as fermenting liquors, or any fluid, when some part escapes in a gaseous form. [ 1913 Webster ]

2. To exhibit, in lively natural expression, feelings that can not be repressed or concealed; as, to effervesce with joy or merriment.

{ } 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. [ 1913 Webster ]

a. [ L. effervescences, p. pr. of effervescere: cf. F. effervescent. ] Gently boiling or bubbling, by means of the disengagement of gas [ 1913 Webster ]