What is the specific name for the boundary beyond which temperatures were low enough for water and other volatile compounds to freeze into solid ice grains?

Answer

Frost line (or ice line)

Closer to the protosun, only rock and metal could condense; further out, beyond the frost line, it was cold enough for volatiles like water to freeze into solid ice grains.

What is the specific name for the boundary beyond which temperatures were low enough for water and other volatile compounds to freeze into solid ice grains?
Originstarplanetsolar systemhypothesis