Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

ernest evans (born october 3, 1941) better known as chubby checker, is a pop singer from the united states.
chubby checker

the corruption perceptions index is an index that shows how corrupt certain countries are.
corruption perceptions index

a patent gives an inventor the right to stop other people making or using their invention.

patent

