Hi, Steve.

Heliopause = the boundary marking the edge of the Sun's influence, roughly 100 AU from the sun, though theory has that it is many times this in the drawn-out wake of the Sun‘s path. It separates the interplanetary medium from the interstellar medium; where the solar wind and the wind from other stars conflict.

Terminal Pause (likely “Termination Shock”?) = is the same border, but this one is believed to be denser, and much closer to the sun, due to incoming cosmic pressure. It is set to face forward in relation to the Sun’s path, similar to the bow shock of a boat traveling through water.

For all the gory details, check out "The Heliosphere", by MIT.

Dan