n. The boundary of heliosphere where the Sun's solar wind is stopped by the interstellar medium.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the boundary marking the edge of the sun's influence; the boundary (roughly 100 AU from the sun) between the interplanetary medium and the interstellar medium; where the solar wind from the sun and the radiation from other stars meet
Word Usage
"The boundary where the pressure from the solar wind and the interstellar medium are at the same pressure, 16 billion kilometres from Earth, forms a giant bubble called the heliopause, and it's nothing like what scientists predicted it to be."