optical

adjective

op·​ti·​cal ˈäp-ti-kəl 

1

: of or relating to the science of optics

2

a

: of or relating to vision : visual

b

: visible sense 1

optical wavelength

c

: of, relating to, or being objects that emit light in the visible range of frequencies

an optical galaxy

d

: using the properties of light to aid vision

an optical instrument

3

a

: of, relating to, or utilizing light especially instead of other forms of energy

optical microscopy

b

: involving the use of light-sensitive devices to acquire information for a computer

optical character recognition

4

: of or relating to optical art

optically

ˈäp-ti-k(ə-)lē 

adverb

Synonyms of optical

• optic
• visual

Examples of optical in a Sentence

The company manufactures microscopes, telescopes, and other optical instruments.

an optical illusion that fools most people

Recent Examples on the Web

Thickness, though, is not always an option—optical films have to stay clear, protective layers on aircraft have to stay light and flexible, and the barriers on outdoor electronics are thin by design. — Jacek Krywko, ArsTechnica, 31 Aug. 2026

This experiment used related transverse polarization gradients, rather than demonstrating the optical Magnus effect itself. — Rupendra Brahambhatt, Interesting Engineering, 30 Aug. 2026

Activity Rings monitor daily movement, exercise, and standing goals, while the optical sensor tracks heart rate throughout the day. — Stackcommerce Team, PC Magazine, 29 Aug. 2026

This led to them obtaining the deepest images ever taken of the Cloud 9 region, approximately ten times deeper than any previous optical imaging of this object. — Robert Lea, Space.com, 28 Aug. 2026

Word History

First Known Use

1570, in the meaning defined at sense 1

Phrases Containing optical

• electro-optical
• magneto-optical
• optical activity
• optical art
• optical bench
• optical disc
• optical disk
• optical fiber
• optical glass
• optical illusion
• optical rotation

Rhymes for optical

• synoptical

Kids Definition

optical

adjective

op·​ti·​cal ˈäp-ti-kəl 

1

: relating to optics

2

: of or relating to vision

3

a

: of, relating to, or using light

an optical telescope

b

: involving the use of a device that senses light to acquire information for a computer

an optical scanner

optically

-k(ə-)lē 

adverb

Medical Definition

optical

adjective

op·​ti·​cal ˈäp-ti-kəl 

1

: of or relating to the science of optics

2

a

: of or relating to vision : visual

b

: using the properties of light to aid vision

an optical instrument

3

: of, relating to, or utilizing light

optical microscopy