I mean why the last "o" is stressed. The second-to-last vowel is usually stressed.
I clicked on it and didn't see the word, therefore I thought it was not., our stateside English has so many quirks that the British do not use. We are working our way to pidgin English the the use of regional and slang wording.
The hints come mostly from the default English sentences, and generally 'big' is starred and 'large' just accepted. The fact that it's not in the hints doesn't mean that it's not accepted.