2. Noun. (astronomy) The theory of the heliocentric model, that the planets including Earth orbit the Sun, in contrast to geocentrism. ¹
3. Noun. (cultural anthropology) A now-defunct theory that all primitive cultures worshipped the Sun and its movements and patterns. ¹
4. Noun. An obsession with the Sun and its movements and patterns. ¹
¹ Source: wiktionary.com