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

To fulfill its mission, HWO will need to maintain stability within its optical system capable of functioning within a marginal width the size of a single atom. —Josh Dinner, Space.com, 12 Jan. 2026

By keeping the same optical size, manufacturers can upgrade to 200 megapixels without redesigning camera modules. —Aamir Khollam, Interesting Engineering, 10 Jan. 2026

As always, never look at the sun without proper optical aid! —Phil Plait, Scientific American, 8 Jan. 2026

This optical gaming mouse has a DPI of 8,000, which is perfect for fast and precise movements. —Bestreviews, Chicago Tribune, 6 Jan. 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 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