What is the difference between "mountain", "hill", and "peak"; "lake" and "pond"; or "river" and "creek?"

There are no official definitions for generic terms as applied to geographic features. The Geographic Names Information System (GNIS) utilizes 43 broad categories of feature classes defined solely to facilitate retrieval of entries with similar characteristics. Go to GNIS Domestic Names Feature Classes to see the full list. 

These categories generally match dictionary definitions, but not always. The differences are thematic and highly subjective. For example, a lake is classified in the GNIS as a "natural body of inland water”, which is a feature description that can also apply to a reservoir, a pond, or a pool. All "linear flowing bodies of water" are classified as stream in GNIS. At least 121 other generic terms fit this broad category, including creek, river, run, fork, etc. Some might contend that a creek must flow into a river, but such hierarchies do not exist in the nation's lexicon. Similarly, the BGN does not have an official definition of hill, mountain, peak.  In summary, there are no official feature classification standards. 

Learn More: Geographic Names FAQs