Top definition. Musk. Though technically the name for the secretion of the male musk deer, musk is most often used as the name for the scent of arousal in both men and women, as actual musk is used in perfumes and colognes. Generally causes arousal for both genders, as it is a secondary sex characteristic.
These photoreceptors are called the rods and cones. Rods are called rods because under the microscope, they are shaped like, of all things, a rod. Finally, those pesky scientists named a structure for what it actually looks like as opposed to someone's unpronounceable last name!
Cones and Rods. This density map shows the retina, which is made up of cones and rods. Cones perceive color and rods perceive shadow in images. In the fovea, which is responsible for sharp central vision, there is huge density of cones but no rods.