to a first approximation

   1.  [techspeak]  When one is doing certain numerical computations, an
   approximate  solution  may  be  computed  by any of several heuristic
   methods,  then  refined to a final value. By using the starting point
   of  a  first  approximation of the answer, one can write an algorithm
   that converges more quickly to the correct result.

   2.  In  jargon,  a  preface  to  any  comment that indicates that the
   comment   is   only  approximately  true.  The  remark  "To  a  first
   approximation,  I  feel  good" might indicate that deeper questioning
   would  reveal  that  not  all is perfect (e.g., a nagging cough still
   remains after an illness).

[glossary]