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: the pseudomonadales are an order of proteobacteria.
Example Output: pseudomonadales

Example Input: monosemy is when the words in a language each have only one meaning.
Example Output: monosemy

Example Input: culgaith is a village and civil parish in eden, cumbria, england.
Example Output:
culgaith