What is the meaning of the word "trial-and-error"?

Definitions:

  1. relating to solving problems by experience rather than theory copy to clipboard adjective
    • they adopted a trialanderror procedure copy to clipboard
  2. trying out various means or theories until error is satisfactorily reduced or eliminated copy to clipboard adjective
    • I argued that all learning is a trialanderror process that resembles biological evolution. copy to clipboard