penis
n. countablen. the external male organ used for urinating and for sex.
n. the primary male external reproductive organ, also serving as the conduit for urine in mammals.
The doctor examined the patient's penis for signs of infection.
In many mammal species, the penis contains a bone called the baculum to help maintain stiffness during mating.
The evolution of the mammalian penis reflects a complex history of sexual selection and physiological adaptation for internal fertilisation.
From late 17th century. Learned borrowing from Latin pēnis (“tail, penis”), from Proto-Indo-European *pes- (“penis”). Displaced native English pintle, tarse, pillicock.
The term is the standard anatomical and medical designation; it is neutral in register but may be considered sensitive in social contexts.