What is "to nurse billiard balls"

Nurse \Nurse\, v. t. [imp. & p. p. Nursed; p. pr. & vb. n. Nursing.]

1. To nourish; to cherish; to foster; as:

   1. To nourish at the breast; to suckle; to feed and tend, as an infant.

   2. To take care of or tend, as a sick person or an invalid; to attend upon.

      Sons wont to nurse their parents in old age.
      --Milton.

      Him in Egerian groves Aricia bore, And nursed his youth along the marshy shore.
      --Dryden.

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.

   By what hands [has vice] been nursed into so uncontrolled a dominion?
   --Locke.

3. To manage with care and economy, with a view to increase; as, to nurse our national resources.

4. To caress; to fondle, as a nurse does.
   --A. Trollope.

   To nurse billiard balls, to strike them gently and so as to keep them in good position during a series of caroms.