Libido

Psychological or sexual drive or energy

The libido or sex drive ( lih-BEE-doh; from Latin libīdō, "lust, desire") refers to a psychological energy that, in common parlance, encompasses all forms of sexual desire, but is sometimes also regarded as the driving force behind other needs, such as a mother's love for her infant. The term was originally coined by the Austrian neurologist Sigmund Freud, the pioneer of psychoanalysis. Initially it referred only to specific sexual needs, but he later expanded the concept to a universal desire, with the id being its "great reservoir".

From Wikipedia, under CC BY-SA. More on occurri.