1. According to Freud, the part of the mind which embodies the instinctive subconcious - the hidden part of the iceberg, if you will. Freud was also the author of the theory that all men want to sleep with their mother, in case you wondered.
2. An internet name, commonly used by bored teenagers on electronic-gaming-oriented forums.
1. "My psychologist says I need to get in touch with my Id."