Source : Webster's Revised Unabridged Dictionary (1913)

Convalesce \Con`va*lesce"\, v. i. [imp. & p. p. {Convalesced};
   p. pr. & vb. n. {Convalescing}.] [L. convalscere; con- +
   valescere to grow strong, v. incho. of valere to be strong.
   See {Vallant}.]
   To recover health and strength gradually, after sickness or
   weakness; as, a patient begins to convalesce.