| Term: | Retreat |
| Definition: | Decrease of the length of a flowline, measured from a fixed point. In practice, when the retreat is of a land-terminating glacier terminus, the fixed point is usually downglacier from the terminus, that is, on the glacier forefield. The quantity reported is most often the amount of retreat rather than the length itself. Advance is the opposite of retreat, that is, advance of the terminus. |