The psychological term coined by Sigmund Freud named after the mythical king of Thebes and the legend based around him. In Greek myth, Oedipus killed his father and married his mother, but without knowledge that either were his parents. Freud's theory proclaimed that, at an unconscious level, a male's sexual preference would be based around the actions and personality of his mother. The male child would also feel extreme animosity towards his father, again at an unconscious level. The phenomenon in females is called the Electra Complex.
The Oedipus Complex is not a group of condos in Coconut Grove, Miami, but rather the explanation that, no matter what you do, it always has to do with you secretly wanting to fuck your mother.
Freudian theory that we all want to fuck our mothers and kill our fathers at some stage in early childhood. It is normal and the emotion need not be suppressed. Three year olds are normally to small to act out this desire.
The origin of gay men according to Freud - it works like the Oedipus complex but the other way around, i.e. little boys want to fuck daddy and kill mummy. Supposedly arises in all little boys, and develops into homosexuality when it's stronger than its hetero inverse.