Synonyms for Rule of thumb:

• n.

  •approximation (noun)
  • estimate,
  • general guideline,
  • guess,
  • hypothesis.
  •guideline (noun)
  • guideline.
  •guidepost (noun)
  • guidepost.
  •modus operandi (noun)
  • method of functioning,
  • workings,
  • method of operating,
  • Mos,
  • method of operation,
  • mode of operation,
  • way of doing things,
  • manner of working.
  •rule that it is wise to follow (noun)
  • hit and miss.
  •standard (noun)
  • be lief,
  • ex-ample,
  • be-lief,
  • ex ample.

• Other synonyms:

  •Other relevant words:
  • trial and error,
  • pragmatic,
  • empiricism,
  • experimentalism,
  • experiment,
  • control experiment,
  • control,
  • tentativeness,
  • controlled experiment,
  • Research and Development,
  • unwritten rule,
  • maxim,
  • trial,
  • trying,
  • criterion,
  • generalization,
  • experimentation,
  • pragmatism,
  • generalisation,
  • testing,
  • experimental method,
  • Experimental Design,
  • approximation.