The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

            I have walked before you from my childhood. --1.
                                                  Sam. xii. 2.
      [1913 Webster]

   2. Children, taken collectively. [R.]
      [1913 Webster]

            The well-governed childhood of this realm. --Sir. W.
                                                  Scott.
      [1913 Webster]

   3. The commencement; the first period.
      [1913 Webster]

            The childhood of our joy.             --Shak.
      [1913 Webster]

   Second childhood, the state of being feeble and incapable
      from old age.
      [1913 Webster]

WordNet (r) 3.0 (2006):

childhood
    n 1: the time of person's life when they are a child
    2: the state of a child between infancy and adolescence [syn:
       childhood, puerility]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "childhood":
   adolescence, babyhood, beginnings, birth, boyhood, cradle,
   freshman year, genesis, girlhood, inception, inchoation,
   incipience, incipiency, incunabula, infancy, maidenhead,
   maidenhood, minority, nascence, nascency, nativity, origin,
   origination, parturition, pre-teens, pregnancy, puberty, subteens,
   teens, youth



The Devil's Dictionary (1881-1906):

CHILDHOOD, n.  The period of human life intermediate between the
idiocy of infancy and the folly of youth -- two removes from the sin
of manhood and three from the remorse of age.