Knighthoods date back to Saxon times. You are 'knighted' by having a sword touched on your shoulders.
Men receiving this honour get called Sir, followed by their real name, like James Bond actor Sir Roger Moore. A knight's wife is called a Lady.
Women get the title Dame, but they don't take part in the accolade (that's the name given to the sword ceremony)
This is a top award so not many are given out.