The term "touchstone of realism" refers to a benchmark or standard of genuine, honest, and believable representation of reality in art, literature, or any other forms of communication. Some synonyms for this phrase may include "yardstick of veracity", "litmus test for authenticity", "measuring stick for truth", "guage of authenticity", "criterion of credibility", "acid test for reality", "test of genuineness", "standard of plausibility", or "marker of actuality". All of these synonyms describe the idea of a touchstone of realism being a critical tool to discern whether something is accurate, truthful, and based on actual experience or observation.