The Collaborative International Dictionary of English v.0.48:

Nurse \Nurse\, v. t. [imp. & p. p. Nursed; p. pr. & vb. n.
   Nursing.]
   1. To nourish; to cherish; to foster; as:
      (a) To nourish at the breast; to suckle; to feed and tend,
          as an infant.
      (b) To take care of or tend, as a sick person or an
          invalid; to attend upon.
          [1913 Webster]

                Sons wont to nurse their parents in old age.
                                                  --Milton.
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                Him in Egerian groves Aricia bore,
                And nursed his youth along the marshy shore.
                                                  --Dryden.
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   2. To bring up; to raise, by care, from a weak or invalid
      condition; to foster; to cherish; -- applied to plants,
      animals, and to any object that needs, or thrives by,
      attention. "To nurse the saplings tall." --Milton.
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            By what hands [has vice] been nursed into so
            uncontrolled a dominion?              --Locke.
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   3. To manage with care and economy, with a view to increase;
      as, to nurse our national resources.
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   4. To caress; to fondle, as a nurse does. --A. Trollope.
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   To nurse billiard balls, to strike them gently and so as to
      keep them in good position during a series of caroms.
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The Collaborative International Dictionary of English v.0.48:

Nursing \Nurs"ing\, a.
   Supplying or taking nourishment from, or as from, the breast;
   as, a nursing mother; a nursing infant.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nursing
    n 1: the work of caring for the sick or injured or infirm
    2: the profession of a nurse
    3: nourishing at the breast [syn: nursing, breast feeding]