Hearsay evidence is "an out-of-court statement introduced to prove the truth of the matter asserted therein". In certain courts, hearsay evidence is inadmissible (the "Hearsay Evidence Rule") unless an exception to the Hearsay Rule applies.

For example, to prove Tom was in town, the attorney asks a witness, "What did Susan tell you about Tom being in town?" Since the witness' answer will rely on an out-of-court statement that Susan made, Susan is not available for cross-examination, and it is to prove the truth that Tom was in town, it is hearsay. A justification for the objection is that the person who made the statement is not in court and thus is insulated from cross examination. Note, however, that if the attorney asking the same question is not trying to prove the truth of the assertion about Tom being in town but the fact that Susan said the specific words, it may be acceptable. For example, it would be acceptable to ask a witness what Susan told them about Tom in a defamation case against Susan because now the witness is asked about the opposing party's statement that constitutes a verbal act.