William Powell Frith in the context of "Victorian painter"

A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields, including signal processing, information theory and biology.

In the First Folio, the plays of William Shakespeare were grouped into three categories: comedies, histories, and tragedies; and modern scholars recognise a fourth category, romance, to describe the specific types of comedy that appear in Shakespeare's later works.

Victorian painting refers to the distinctive styles of painting in the United Kingdom during the reign of Queen Victoria (1837–1901). Victoria's early reign was characterised by rapid industrial development and social and political change, which made the United Kingdom one of the most powerful and advanced nations in the world. Painting in the early years of her reign was dominated by the Royal Academy of Arts and by the theories of its first president, Joshua Reynolds. Reynolds and the academy were strongly influenced by the Italian Renaissance painter Raphael, and believed that it was the role of an artist to make the subject of their work appear as noble and idealised as possible. This had proved a successful approach for artists in the pre-industrial period, where the main subjects of artistic commissions were portraits of the nobility and military and historical scenes. By the time of Victoria's accession to the throne, this approach was coming to be seen as stale and outdated. The rise of the wealthy middle class had changed the art market, and a generation who had grown up in an industrial age believed in the importance of accuracy and attention to detail, and that the role of art was to reflect the world, not to idealise it.

In the late 1840s and early 50s, a group of young art students formed the Pre-Raphaelite Brotherhood as a reaction against the teaching of the Royal Academy. Their works were based on painting as accurately as possible from nature when able, and when painting imaginary scenes to ensure they showed as closely as possible the scene as it would have appeared, rather than distorting the subject of the painting to make it appear noble. They also felt that it was the role of the artist to tell moral lessons, and chose subjects which would have been understood as morality tales by the audiences of the time. They were particularly fascinated by recent scientific advances which appeared to disprove the Biblical chronology, as they related to the scientists' attention to detail and willingness to challenge their own existing beliefs. Although the Pre-Raphaelite Brotherhood was relatively short-lived, their ideas were highly influential.

Opera glasses, also known as theater binoculars or Galilean binoculars, are compact, low-power optical magnification devices, usually used at performance events, whose name is derived from traditional use of binoculars at opera performances. Magnification power below 5× is usually desired in these circumstances in order to minimize image shake and maintain a large enough field of view. A magnification of 3× is normally recommended. The design of many modern opera glasses of the ornamental variety is based on the popular lorgnettes of the 19th century. Often, modern theatre binoculars are equipped with an LED flashlight, which makes it easier to find a place in the dark.

In addition to the more stereotypical binocular type, folding opera glasses were another common design. They were made mostly of metal and glass, with a leatherette cover for grip and color. Although folding glasses have existed in one form or another since the 1890s, they were perhaps most popular in the mid-20th century and many from this era are marked "Made in Japan" or, less commonly, "Made in Occupied Japan". The design can still be purchased new, although the most common contemporary designs are now almost entirely plastic.