Bridges: Some scientists might call these “wormholes.” These are the passageways travelers use to go back and forth in time. Veils exist just outside the entry and exit points of bridges.
Exotic Matter: Exotic matter, or negative matter, is the substance used to hold open bridges so that they won’t collapse in on themselves. You can get more scientific by looking at this link.
Duronium: Duronium is the other element besides exotic matter that travelers need to get through bridges. It’s a metal that can’t be found on a periodic table. Emerson, Michael, and Liam all have duronium rings. So does Kaleb’s mother, Grace. Kaleb has a duronium disk engraved with the word “HOPE.”
Ripple, or Rip: A rip in the Hourglass world is a person who lived in the past or will exist in the future who “bleeds through” time. Some might consider these to be ghosts, but they are very different. Emerson can make rips disappear by touching them.
Time Gene: A gene that gives people different abilities relating to time. (See character descriptions for more detailed information.)
Time Slip: A time slip is much like a ripple, but rather than one person, it’s a scene that “bleeds through” time. These show up at the end of Hourglass, and are a sign that something is desperately wrong with the space time continuum.
Space Time Continuum: See here.
Veil: A veil is a holding space, almost like a waiting room into a bridge, and can sometimes be seen as a shimmer in the air. There are a few time related abilities that allow access to veils. A traveler can get into a veil as long as they have duronium, and they do not need exotic matter to access them. (This allows veils to be used as hiding places.)
The Doctor: The Doctor is Myra’s imaginary boyfriend. He has a super sweet blue police box that he uses to travel through time. For the truth about The Doctor, see BBC America.
The Hourglass will neither confirm or deny the validity of the material linked above.