In space operas is it common to divide interstellar space into sectors and/or quadrants containing at least several stars each.
Star Trek TOS used both "sector" and "quadrant" as divisions of interstellar space.
Whether sector and quadrant referred to the same type of division or not in a specific work of fiction, they are definitely different words, so the correct answer for quadrant may not be the correct answer for sector.
James White's "Sector General" stories, beginning in the November 1957 issue of New Worlds is set in a giant space station used as an interstellar hospital, Sector Twelve General Hospital.
I'm sure there are many earlier examples.