How to memorize the Encyclopedia Britannica and a dictionary?

I would like to learn the britannica to have general knowledge on all kinds of subjects but as the vocabulary is complicated for me I have to learn the dictionary as well but I don’t know how to go about learning both. What are the most efficient and least difficult techniques for both?

And a question that has nothing to do with anything but I would like to subscribe to memory League but as I don’t intend to participate in championships, what is the use of memorizing cards, names, words etc.?