A mittimus (Latin for “we send”) is a court order directing a jail or prison to detain a criminal defendant either before or after sentencing.
The Code of Massachusetts Regulations (103 CMR 410) defines a mittimus as
The sentencing document(s) issued by the court committing the inmate to incarceration that contains sentence information to include offense, term of imprisonment and any other orders made by the court.
The document, which is addressed to the official in charge of the correctional facility receiving it, also contains the detainee’s case number as well as his personal information–date of birth, social security number, etc.