ego

1. (psychology, Freudian) The most central part of the mind, which mediates with one's surroundings.Examples: "In the well adjusted person the ego is the executive of the personality and is governed by the reality principle."; "‘Everything begins with “I”, you mean. Which is ego,’ said Tom, placing an ankle behind his ear, ‘not id.’"

2. (anthropology, genealogy) The individual from whose point of view a family tree or pedigree chart is drawn, or the reference point from whom kinship terminology is relative. (Used without the definite article the.)Examples: "the cousin of ego on the father's side"