Piths are the central or essential parts of something. Synonyms for piths include core, marrow, essence, heart, soul, center, nucleus, kernel, and hub. These words all convey the idea of something being at the center or most important part of a larger whole. They can be used in a variety of contexts, from describing the essence of a literary work to discussing the core message of a speech or presentation. Whether you use piths, core, or any of these other synonyms, the idea remains the same: something is at the very heart or center of a larger entity.