Definitions are quick and concise. When you need a rough estimation as to the meaning of a word, you look to a dictionary, but if you’re searching for something a bit more substantial, your average dictionary is useless.
So you turn to an encyclopedia. An encyclopedia entry for a given word is where you will find something closer to the words full meaning. It provides you with history, connotation, denotation, and in the case of theoretical ideas and concepts, it sometimes provides you with further readings.
Quickly skimming a dictionary entry isn’t going to teach you the meaning of a word. It’s going to give you somewhere to start. It’s incomplete, rough, and loose. If you want to know the difference between, say, prejudice and racism, don’t start at the dictionary and immediately stop, thinking you’ve got it all figured out. Read up on the history of racial inequality, give the words context.
To be intelligent isn’t to just having bits of information at the ready, but to be able to relate those bits, to find patterns.
“There’s a big difference between knowing the name of something and knowing something” – Richard Feynman