I'm English but I speak Spanish to a good level. I lived in Spain for a year and I have a degree in the language, so I'm definitely not a beginner.

Although I find it fairly easy to have conversations in Spanish, I struggle when reading because there are words in every sentence that I don't understand when I read a novel.

Instead of using a Spanish-English dictionary, I would like to buy myself a dictionary that is in Spanish only - in the same way that I would buy an English dictionary that just gives the definition, not a translation.

I don't know of any publishers or any types of dictionaries that would be good in Spanish, so does anyone have recommendations for one that I could buy in paper copy, perhaps from Amazon?

I am studying Spanish (right from the basics) as a course in college.

As I'll be using the dictionary for academic purposes, I want it to be from a reliable source, and accurate for the most part.

For example, Merriam Webster, Oxford, etc. are renowned English dictionaries; I would like something similar for Spanish.

Thanks in advance!

Edit: As of now, I have come across Collins Spanish Dictionary, and need opinions on it.