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

That includes central processors, or CPUs, switch chips, chips for optical networking, chips for laptops, Jetson chips for robots and cars, and the chip inside Nintendo's Switch 2 gaming console. — Kai Nicol-Schwarz, CNBC, 28 Sep. 2026

Star Catcher plans to use the mission to transmit optical power between two independent spacecraft. — Aamir Khollam, Interesting Engineering, 28 Sep. 2026

Speaking of the oversized, the collection’s Handloom Cardigan fits the bill but spares you from imitating a balloon, courtesy of those vertical stripes (also known as the oldest optical trick in the fashion book). — Stacia Datskovska, Footwear News, 28 Sep. 2026

Geologist, working with visual artist Kyle Simon, accomplished this by fitting a telescope with optical lenses. — Justin Klawans, TheWeek, 28 Sep. 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