The Collaborative International Dictionary
Incontestability
Incontestability \In`con*test`a*bil"i*ty\, n. The quality or state of being incontestable.
Wiktionary
incontestability
n. 1 The characteristic of being incontestable. 2 (context legal English) In United States trademark law, the state of having been registered as a trademark for more than five consecutive years without a challenge, and therefore conclusively presumed not to cause confusion with any other trademark, and to have acquired distinctiveness.