peripheral

American  

[puh-rif-er-uhl] / pəˈrɪf ər əl /

adjective

1. relating to, situated in, or constituting the periphery.

   peripheral resistance on the outskirts of the battle area.

2. concerned with relatively minor, irrelevant, or superficial aspects of the subject in question.

3. Anatomy. near the surface or outside of; external.

4. Computers. relating to a device or unit that is separate from but connected to a computer, network host, etc.

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noun

1. Computers.

   1. a device or unit that operates separately from the CPU but is connected to it, such as a mouse, printer, speakers, etc.

   2. a device or unit that is separate from a network’s host computer but in communication with it, such as a shared input terminal, printer, or backup drive.

peripheral British  

/ pəˈrɪfərəl /

adjective

1. not relating to the most important part of something; incidental, minor, or superficial

2. of, relating to, or of the nature of a periphery

3. anatomy of, relating to, or situated near the surface of the body

   a peripheral nerve

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peripheral Scientific  

/ pə-rĭf′ər-əl /

1. Anatomy Relating to or being the surface or outer part of a body or organ.

2. Relating to or being part of the peripheral nervous system.

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1. Computer Science An auxiliary device, such as a printer or modem, distinct from a computer's central processing unit and working memory, and often connected externally.

peripheral Cultural  

1. Any part that is separate from a computer's CPU, such as a printer, a keyboard, or a monitor.

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Other Word Forms

• peripherally adverb
• unperipheral adjective

Etymology

Origin of peripheral

First recorded in 1800–10; 1965–70 peripheral for def. 4; from Greek peripher(ḗs) ( periphery ( def. ) ) + -al ¹ ( def. )

Example Sentences

"We've all had that moment of wandering into a club and scanning the room with your peripheral vision and being like, 'Are they there? Are they there?'" she says.

From BBC • Apr. 2, 2026

Traditional CAR-NK approaches usually depend on mature NK cells collected from sources such as peripheral blood or cord blood.

From Science Daily • Feb. 17, 2026

For decades, U.S. macroeconomic debates treated regulation as a sideshow—important for lawyers, lobbyists, and compliance officers but peripheral to the “real” drivers of economic performance, such as interest rates, deficits, and stimulus.

From Barron's • Feb. 2, 2026

In Europe, government bond yield spreads between peripheral eurozone countries and German Bunds tightened further, with Italian and Spanish spreads reaching new milestones and hitting levels unseen since 2008, according to LSEG.

From The Wall Street Journal • Jan. 16, 2026

I’m not looking directly at him, but I can see him in my peripheral vision.

From "Water for Elephants" by Sara Gruen

Related Words

• incidental
• tangential