Collateral evidence refers to any evidence or information that indirectly supports a conclusion or argument. Synonyms for collateral evidence include circumstantial evidence, indirect evidence, secondary evidence, supporting evidence, and corroborative evidence. Circumstantial evidence refers to evidence that may not directly prove a conclusion but suggests it is likely. Indirect evidence refers to evidence that provides indirect support for a conclusion. Secondary evidence refers to information that supports an argument or conclusion by verifying primary evidence. Supporting evidence refers to evidence that supports and strengthens a conclusion or argument. Corroborative evidence refers to evidence that confirms or supports a particular conclusion or theory. Using these synonyms can help to clarify the meaning of collateral evidence in different contexts.