[Wolfram MathWorld][1] says

> As used in physics, the term “exact” generally refers to a solution that captures the entire physics and mathematics of a problem as opposed to one that is approximate, perturbative, etc. Exact solutions therefore need not be closed-form. 

But [Terry Tao][2] seems to take "exact solution" to mean a closed form solution. 

Is one of these very standard?  Or does usage just vary on this point?


  [1]: https://mathworld.wolfram.com/ExactSolution.html
  [2]: https://terrytao.wordpress.com/2007/03/18/why-global-regularity-for-navier-stokes-is-hard/