To support or enhance the believability of a fact or assertion by the presentation of additional information that confirms the truthfulness of the item.
The testimony of a witness is corroborated if subsequent evidence, such as a coroner's report or the testimony of other witnesses, substantiates it.
v. to confirm and sometimes add substantiating (reinforcing) testimony to the testimony of another witness or a party in a trial. (See: corroborating evidence)