genericized trademark

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

• noun A brand name or trademark of a successful product, that has come into general use to refer to the generic class of objects rather than the specific brand type, with the exclusive rights to said product being lost by the parent company, either due to legal action or inappropriate following of trademark law. Examples include Brassiere, Escalator, Touch-tone. Compare to proprietary eponym.