"The coach wants the first horse."
Translation:De coach wil het eerste paard.
I'm seeing paard as the translation for horse. I'm looking at the exercise on the Duolingo website. If you're working from the app, sometimes it gives you a different translation. Paard should be counted as correct. A knol is an old, worn-out horse (more or less).
I think it sometimes also has to do with the de/het article. It is "het paard" en "de knol". If you accidentally type "de paard", duolingo might correct it to "de knol" based on the article you used (bringing out a synonym that does use "de"), instead of to "het paard" based on the noun you used (which would be more logical).