common name

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A common or vernacular name as distinguished from a scientific name, as water moccassin or cotton mouth for the snake Agkistrodon piscivorus.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The name by which a species is known to the general public, rather than its taxonomic or scientific name.