OYER AND TERMINER By SovConn | April 22, 2013 oyer and terminer (oy-<>r an[d] t<>r-m<>-n<>r). [Law French oyer et terminer “to hear and determine”] 1.COMMISSION OF OYER AND TERMINER . 2.COURT OF OYER AND TERMINER. [Blacks Law 8th] Posted in Law Dictionary Definitions