A rumour, or an erroneous or improbable story.
Information that was heard by one person about another that cannot be adequately substantiated.
Evidence based on the reports of others, which is normally inadmissible because it was not made under oath, rather than on personal knowledge.
An out-of-court statement offered in court for the truth of the matter asserted, which is normally inadmissible because it is not subject to cross-examination unless the hearsay statement falls under one of a number of exceptions.