Two of three equal parts of a divisible whole(noun)
WordNet. Princeton University. 2010.
Use "two-thirds" in a sentence
"The evidence at trial showed that the 1978 Bronco is an unstable sport utility vehicle that Ford marketed for American families with a roof that is two-thirds plastic/one-third steel and has no roll bar."
"Any statute or ordinance can be revised or repealed by a majority of the appropriate legislative body, but amending the Constitution requires approval by two-thirds of both houses of Congress and then ratification by three-fourths of the states."
"As the Bronco rolled two and a half times, the two-thirds of the roof that was plastic broke off completely at the roof pillars and crashed into the occupant compartment; the front steel portion flattened to the dashboard."