OPTICAL

[adjective] [not gradable] - connected with the eyes or sight, or connected with or using lightan optical effectan optical microscope/telescopeCDs are optical (= using light) storage media, unlike hard or floppy disks which are magnetic storage media.In computing, optical character recognition ( OCR) is the process by which an electronic device recognizes written letters or numbers.An optical fibre is a long thin glass rod through which very large amounts of information can be sent in the form of light.Many TV and telephone signals are now distributed through optical fibres. See also fibre optics at fibre.An optical illusion is something that you think you see, but which is not really there.In the desert, the heat can sometimes cause people to see palm trees which aren't really there, but are just optical illusions.