Short answers, pulled from the story.
Hyperspace is a science fiction concept describing a higher-dimensional or parallel space through which interstellar distances can be crossed faster than light. Ships typically enter it via a device called a hyperdrive and navigate it through a process referred to as "jumping".
The word hyperspace in a space-travel context was first used by John Campbell in his story Islands of Space, published in Amazing Stories Quarterly in 1931. The related term "hyper-drive" is first recorded in a 1946 preview of Murray Leinster's story "The Manless Worlds" in Thrilling Wonder Stories.
The "star streaks" effect used in Star Wars (1977) was first created by special effects designer Dan O'Bannon for the 1974 film Dark Star, which is considered the first cinematic depiction of a ship jumping into hyperspace. Star Wars adopted the same visual and it became one of the franchise's defining images.
In the 1951 novel Foundation, Asimov described hyperspace as an "unimaginable region that was neither space nor time, matter nor energy, something nor nothing" through which a ship could traverse the entire Galaxy in the interval between two neighboring instants of time. The Foundation series began appearing in Astounding magazine in 1942.
Science fiction writers use two models: the folding model, popularized by Robert A. Heinlein's Starman Jones (1953), in which three-dimensional space is bent through a higher dimension to bring distant points together; and the mapping model, illustrated by Bob Shaw's Night Walk (1967), in which hyperspace is a smaller parallel universe that functions as a shortcut.
E. C. Tubb is credited with playing an important role in developing hyperspace lore through space operas he wrote in the early 1950s. He was among the first writers to treat hyperspace as a central part of the plot rather than a convenient mechanism that simply enabled faster-than-light travel.