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.

[EX Q]: margaret colin (born may 26, 1958) is an american actress.
[EX A]: margaret colin

[EX Q]: the vickers machine gun (also known as the vickers gun) was a machine gun that was used by the british army from 1912 to 1968.
[EX A]: vickers machine gun

[EX Q]: a fist is the the term given to the hand when the four fingers are clenched, and the thumb closed over the first finger.
[EX A]:
fist