from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A graph of flow past a point in a river versus time.
- n. A graph of water table versus time.
from The Century Dictionary and Cyclopedia
- n. A diagram showing the heights of water in a river day by day during any interval.
- n. An apparatus for automatically recording the height of water in rivers or in wells, analogous to the limnograph for lakes or to a self-recording tide-gage for oceans. It has a vertical scale for the height of water and a horizontal scale for the time.
hydro- + -graph (Wiktionary)