A genetic disorder in which a female's breasts are extrodinarily larger than the size of the individual's head.
To determine whether or not a female has canoons, you will have to calculate the radius of one entire breast, and multiply it by 3.14 to get the external surface area. Compare the surface area of the head to the surface area of the breast and if the breast is larger than that the surface area in that of the head, than the female infact has CANOOOOOONS.
(in extreme cases, it is possible for males to have canoons)
Breast Size = 30cm(square)
Head Size = 15cm(square)
Since the breast size is double the head surface area, this person would have canoons.