A more thorough explanation:

Oyer and terminer is a legal term that comes from the Law French phrase "oyer et terminer," which means "to hear and determine." It can refer to two things:

1. A commission of oyer and terminer
2. A court of oyer and terminer

1. A commission of oyer and terminer might be issued by a king or queen to investigate a particular crime or set of crimes. For example, in 1675, King Charles II issued a commission of oyer and terminer to investigate the "Popish Plot," a supposed conspiracy by Catholics to assassinate him and put his brother James on the throne.

2. A court of oyer and terminer is a type of court that has the power to hear and determine criminal cases. For example, in the United States, some states have courts of oyer and terminer that are responsible for trying serious criminal cases, such as murder.

The examples illustrate the two different meanings of the term "oyer and terminer." The first example shows how a commission of oyer and terminer might be used to investigate a particular crime or set of crimes. The second example shows how a court of oyer and terminer might be used to try serious criminal cases. Both examples demonstrate the idea of "hearing and determining" a legal matter, which is the essence of the term "oyer and terminer."