[syn: piggyback, pickaback, pig-a-back]
The Collaborative International Dictionary of English v.0.48:
Pickaback \Pick"a*back`\ (p[i^]k"[.a]*b[a^]k`), adv.
   On the back or shoulders; as, to ride pickback. [Written also
   pickapack, pickback, and pickpack.]
   Syn: piggyback.
        [1913 Webster +PJC]
              A woman stooping to take a child pickaback.
                                                  --R,Jefferies.
        [1913 Webster]
WordNet (r) 3.0 (2006):
pickaback
    adv 1: on a railroad flatcar; "the trailer rode piggyback across
           the country" [syn: piggyback, pickaback,
           pig-a-back]
    2: on the back or shoulder or astraddle on the hip; "she carried
       her child piggyback" [syn: piggyback, pickaback,
       pig-a-back]