Here's why:
* Entry words are the main words listed in a dictionary, usually in alphabetical order. They are the words you look up to find definitions, pronunciations, and other information.
* Guide words are the words that appear at the top of each page in a dictionary, indicating the first and last entry words on that page. They help you quickly find the section where your desired word might be located.
Since "trout" is the word you would look up in a dictionary to find its meaning, it's an entry word.