In geometry, a tesseract
means the fifth dimension. In the world of A Wrinkle in Time
, a tesseract is that as well, but also an exciting and dangerous way to travel through space and time, as the Mrs. W's and the children do. Mrs. Whatsit attempts to explain it exactly to Meg, Charles, and Calvin in Chapter 5, but a tesseract is essentially a shortcut between two points in space and time: a "wrinkle" in time. Mr. Murry and the U.S. government were experimenting around with tesseracts, and he was accidentally whisked off to the dark planet Camazotz; it is by tessering that the more skilled Mrs. W's take the children around the universe. When Mrs. Whatsit casually mentions a tesseract at the beginning of the story to Mrs. Murry, who turns white, she marks the beginning of the adventure to save Mr. Murry.