Pornography (from Ancient Greek (porni) "prostitute" and (grafi) "writing"), more informally referred to as porn or porno, is the representation of the human body or sexual activity with the goal of sexual arousal. It is similar to, but distinct from erotica, though the two terms are often used interchangeably.
In general, "erotica" refers to portrayals of sexually arousing material that hold or aspire to artistic or historical merit, whereas "pornography" often connotes the prurient depiction of sexual acts, with little or no artistic value. The line between "erotica" and the more pejorative term "pornography" is often highly subjective. In practice, pornography can be defined merely as erotica that is perceived as "obscene". The definition of what one considers obscene can differ among persons, cultures and eras. This leaves legal actions by those who oppose pornography open to wide interpretation.
Pornography may use any of a variety of media — printed literature, photos, sculpture, drawings, sound recording, film or video, and may even be performed in a live venue, possibly in front of a live audience. Notably, all of the above may be found on the Internet.
The concept of pornography as understood today did not exist until the Victorian era. Its current definition was added in the 1860s, replacing the older one meaning writings about prostitutes.
In its original meaning, pornography was literally "writing about prostitutes", from the classical Greek roots. It derived from a Greek term for men who chronicled the well-known "porni" (or skilled prostitutes of ancient Greece). In more modern times, the term was adopted by social scientiststs to describe the work of men like Nicholas Restif and William Acton, who in the 18th and 19th centuries published treatises studying prostitution and proposing to regulate it. It first appears in an English medical dictionary in 1857 defined as "A description of prostitutes or of prostitution, as a matter of public hygiene." Within 5 years though, the second, obscene definition appeared in Webster's Dictionary. "Licentious painting or literature; especially, the painting anciently employed to decorate the walls of rooms devoted to bacchanalian orgies." The term kept its first, neutral meaning in the Oxford English Dictionary until 1905. The term now refers to sexually explicit material of all kinds, particularly that which is prohibited, regulated or condemned by figures of authority.