Princeton's WordNet(0.00 / 0 votes)Rate this definition: 1  shimmer, play(verb) a weak and tremulous light. 2  shimmer(verb) shine with a weak or fitful light. 3  shimmer(verb) give off a shimmering reflection, as of silk.
CONE CELLS are the second type of light sensitive cells in the retina of the eye. The human retina contains 6-7 million cones; they function best in bright light and are essential for acute vision (receiving a sharp accurate image).
For those with normal vision, the three types of cones allow vision of about one million distinctive colors. Some animal species including certain birds, insects, fish, and reptiles, have a fourth type of cone cell that extends color perception into the UV range.