The vagina (vaginæ, plural), derived from the Latin word for sheath, is the tubular tract leading from the uterus to the exterior of the body in the female of mammals, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the oviduct.
"Vagina" is normally used in non-scientific parlence to refer to entirety of the female genitalia. This is inacurate however. It retains great cultural significance as the primary female sexual organ.