From the Random House Dictionary of the English Language:

1

• From the Random House Dictionary of the English
  Language
• de?fine (di fin?), v.t., -fined, -fin-ing.
• to state or set forth the meaning of a (word,
  phrase, etc.) A careful person defines his
  terms.
• to explain the nature or essential qualities of
  describe to define financial functions.
• to determine or fix the boundaries or extent of
  to define property with stakes.
• to make clear the outline or form of The artist
  defined the roof of the barn boldly against the
  sky.

2

• Define the random variable of interest explain
  the nature or essential qualities of it describe
  it in words.
• State its distribution.
• Binomial, Geometric, Negative Binomial,
  HyperGeometric,, Poisson, etc., are not
  distributions they are families of
  distributions.
• You must specify all parameters required to
  distinguish one member of the family from
  another.
• Restate the problem using the random variable
  that you have defined.
• Solve the problem using this random variable,
  making clear how you are using it in the solution.