|1.||a river in W Europe, rising in S Switzerland in the Rhône glacier and flowing to Lake Geneva, then into France through gorges between the Alps and Jura and south to its delta on the Gulf of Lions: important esp for hydroelectricity and for wine production along its valley. Length: 812 km (505 miles)|
|2.||a department of E central France, in the Rhône-Alpes region. Capital: Lyon. Pop: 1 621 718 (2003 est). Area: 3233 sq km (1261 sq miles)|
Lyon Ly·on (lī'ən), Mary Francis. Born 1925.
British geneticist whose research on mice led to her formulation of the Lyon hypothesis.