Old legal concepts refer to carnal knowledge as the knowledge of body and flesh in a sexual sense. Although the term is quite obsolete, it is continued to be used by some in legal terms. This is because some laws that continue to be enforced use this term. However, the actual definition of carnal knowledge may vary among jurisdictions.
Carnal knowledge involves the definition of sexual intercourse as well as who constitutes as a participant. The legal concept of carnal knowledge evolved from the 19th and 20th century when many laws that were enacted barred some forms of sexual activities. Some definitions include consensual and non-consensual sexual activity or sexual intercourse with a 10 year old and even rape. At present, the definition of carnal knowledge is limited to sexual intercourse. Past definitions were more detailed as compared to the present definition.
It is generally believed that carnal knowledge involves consensual sexual intercourse. However, there are a few exceptions to this definition. It is usually used to describe sexual relations between minors, those who are below the age of consent or majority. This definition can also extend to those who have a 4-year age gap or more, if one of the persons involved is a minor. Some jurisdictions prefer to use the modern term of statutory rape, while other jurisdictions reserve the term statutory rape to describe a greater age difference between consensual sexual intercourse partners.
Carnal knowledge involving a minor is usually considered a felony, and may be colloquially referred to as a sex crime.