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.

Example Input: an eponym is a person's name that is used to name something else.
Example Output: eponym

Example Input: land of the free is the national anthem of belize.
Example Output: land of the free

Example Input: colour or color is a property of light as seen by people.
Example Output:
colour