What's the word for "believing one is the center of the universe"? [duplicate]

The word egoist is slightly different from egotist; its senses include “An egocentric or self-centered person”. Narcissist, with sense “One who shows extreme love and admiration for himself or herself”, and solipsist, “One who adheres to self-absorption and an ignorance of the views or needs of others”, may be relevant too.

Edit: As mentioned in comments and as used in the definition of egoist above, egocentric has senses like “selfish, self-centered” and “egotistical”. It also has a less-obvious sense:

Relating to spatial representations: linked to a reference frame based on one’s own location within the environment (as when giving the direction as “right” rather than “north”); opposed to allocentric.

[Link sources: wiktionary and ELU 1,2,3,4].