A humanoid is any species that follows the basic bipedal body design of Humans. Most have two arms, one head, two eyes and one mouth, but the number of these and other features does not in itself determine a humanoid. Humanoids are the most common form of sapient life throughout the universe.
Many humanoids include some gender differentiation. Males are generally more muscular, while females generally have more hourglass-shaped bodies with wider hips and, if they are mammals, breasts; both of which are adaptations for child-rearing. Genitalia is usually located in the groin region and also differs between genders, allowing for sexual reproduction.
Because of their shared form, many humanoid species find other humanoid species physically attractive. For example, almost any straight humanoid male appreciates a scantily-clad Twi'lek dancer, and any Zeltron appreciates practically any other humanoid being. However, such attraction and physical similarities do not guarantee reproductive compatibility. For example, although Humans and Vulcans appear to differ physically only in their ears, eyebrows and haircuts, they are unable to produce surviving offspring together without extreme medical intervention.
Most humanoids are sentient thanks to their brain-to-body mass ratio, but Ormazoids and politicians are notable exceptions.