A light-sensitive cell in the retina of the eye that can also distinguish colours. The other type of light-sensitive cell is called a rod. There are around six million cones in the human retina and these are thought to comprise three types that are sensitive to the three primary colours of red, blue, and green. (See EYE.)

A cone biopsy is a surgical technique in which a conical or cylindrical section of the lower part of the neck of the womb is excised.