Source : Webster's Revised Unabridged Dictionary (1913)

Childhood \Child"hood\ (ch[imac]ld"h[oo^]d), n. [AS. cildh[=a]d;
   cild child + -h[=a]d. See {Child}, and {-hood}.]
   1. The state of being a child; the time in which persons are
      children; the condition or time from infancy to puberty.

            I have walked before you from my childhood. --1.
                                                  Sam. xii. 2.

   2. Children, taken collectively. [R.]

            The well-governed childhood of this realm. --Sir. W.
                                                  Scott.

   3. The commencement; the first period.

            The childhood of our joy.             --Shak.

   {Second childhood}, the state of being feeble and incapable
      from old age.

Source : WordNet®

second childhood
     n : mental infirmity as a consequence of old age; sometimes
         shown by foolish infatuations [syn: {dotage}, {senility}]