A more thorough explanation:

Definition: In retentis is a legal term used in Scots law which means "among things withheld". It refers to evidence that is subject to reservation.

For example, evidence might be taken in retentis if a witness is mortally ill and unable to testify at the time of the trial. The evidence would be set aside until the witness is able to testify or until the proper time to produce it.

This term is used to describe evidence that is being held back or reserved for a later time. It is important in legal proceedings to ensure that all evidence is presented in a fair and timely manner.