The term 'idm' appears to be a typographical error, and it likely refers to the word "id." In psychology, "id" represents the part of the mind that is responsible for instinctual impulses and drives. It is one of the three components of Sigmund Freud's model of the human psyche, along with the ego and the superego. The id operates based on the pleasure principle, seeking immediate gratification of desires and needs without considering consequences.
The word "id" comes from Latin, meaning "it." Freud adopted the term in the early 20th century to represent the unorganized part of the personality structure.