What is an easy way to classify a word?

I want to write a program that can classify the input. For example, if the input is Japan, it should output country. For reddit --> website. Ferrari --> car. For certain things it is as easy as looking at the first sentence of Wikipedia for that word. But I want to get more specific such as Ferrari --> car --> sports car, or reddit --> website --> website with user generated content. I am sure people have done this in NLP, a pointer to where I should start would be very much appreciated.