I have a weird question

What does the word "esoteric" mean? Was it used a lot in the book, "The Secret" by Rhonda Byrne, and I'm wondering if this is a word with law of attraction principles behind it. I heard someone say this word on Tv and they had like this exotic accent, and I was like, I wish I knew what this word actually meant, and how to use it within the context of a sentence.