A more thorough explanation:

The tender-years hearsay exception is a legal rule that allows certain statements made by young children to be admitted as evidence in court, even though they would normally be considered hearsay and therefore inadmissible. Hearsay is an out-of-court statement made by someone other than the witness testifying in court, and it is generally not allowed because it is considered unreliable.

The tender-years hearsay exception applies specifically to statements made by children who are ten years old or younger, and who are describing an act of physical or sexual abuse. If the child is unavailable to testify in court, and if the court determines that the time, content, and circumstances of the statement make it reliable, then the statement may be admitted as evidence.

For example, if a young child tells a teacher or a social worker that they have been physically or sexually abused by a parent or caregiver, and the child is too young or traumatized to testify in court, then the teacher or social worker may be allowed to testify about what the child said. This is because the child's statement is considered reliable under the tender-years hearsay exception.