The Collaborative International Dictionary of English v.0.48:

imprinting \im*print"ing\, n. (Ethology, Psychology)
   The learning of a behavioral pattern that occurs soon after
   birth or hatching in certain animals, in which a long-lasting
   response to an individual (such as a parent) or an object is
   rapidly acquired; it is particularly noted in the response of
   certain birds to the animal they first see after hatching,
   usually the parent, as in ducks who will follow the adult
   duck they first see.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Imprint \Im*print"\, v. t. [imp. & p. p. Imptrinted; p. pr. &
   vb. n. Imprinting.] [OE. emprenten, F. empreint, p. p. of
   empreindre to imprint, fr. L. imprimere to impres, imprint.
   See 1st In-, Print, and cf. Impress.]
   1. To impress; to mark by pressure; to indent; to stamp.
      [1913 Webster]

            And sees his num'rous herds imprint her sands.
                                                  --Prior.
      [1913 Webster]

   2. To stamp or mark, as letters on paper, by means of type,
      plates, stamps, or the like; to print the mark (figures,
      letters, etc., upon something).
      [1913 Webster]

            Nature imprints upon whate'er we see,
            That has a heart and life in it, "Be free."
                                                  --Cowper.
      [1913 Webster]

   3. To fix indelibly or permanently, as in the mind or memory;
      to impress.
      [1913 Webster]

            Ideas of those two different things distinctly
            imprinted on his mind.                --Locke.

   4. (Ethology) To create or acquire (a behavioral pattern) by
      the process of imprinting.
      [PJC]

WordNet (r) 3.0 (2006):

imprinting
    n 1: a learning process in early life whereby species specific
         patterns of behavior are established