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

• peripherals
  plural

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

Derived Forms

• unperipheral
  adjective
• peripherally
  adverb

Inflected Forms

Nouns

• peripherals
  plural

Etymology

Origin of peripheral

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

Explanation

Scanners, printers, and speakers are peripheral devices for a computer because they aren't central to the working of the computer itself. Anything peripheral is on the margin, or outside, while main things, like a computer's processor, are not peripheral. Outside of computer jargon, peripheral is a common term in eye exams, which measure peripheral vision to see how far toward the outer right and left edges you can see. Peripheral also describes nerves from the body's peripheral system, which are secondary to the main system but branch off of it — like the wires between peripheral devices and a computer.

Example Sentences

See Examples For:

peripheral peripherals

Suddenly, it was blurry and her peripheral vision waned.

From The Wall Street Journal ● Sep. 19, 2026

What may be arguably new is treating the audiences for historically marginalized forms of art as central rather than peripheral.

From Los Angeles Times ● Sep. 9, 2026

As Hibbert's tumour began to press on his optic nerves, it narrowed his peripheral vision.

From BBC ● Aug. 26, 2026

"Now that we know that these immune cells actually can get into the brain, we can think about all kinds of new engineering strategies to have those peripheral immune cells do useful things."

From Science Daily ● Aug. 14, 2026

His peripheral vision showed more trees coming his way, the Berg dipping lower now so that there’d be no chance of his making it through.

From "The Kill Order (Maze Runner, Book Four; Origin)" by James Dashner

The personal computer and killer apps such as spreadsheets fueled an explosion of demand that far offset that falling price: between 1974 and 1984, business investment in computers and peripherals tripled to 0.8% of GDP.

From The Wall Street Journal ● Oct. 2, 2026

The low forward P/E ratios for Sandisk and Micron haven’t only resulted from the hot market for memory chips and computer memory peripherals.

From MarketWatch ● Jul. 17, 2026

The first AI category is investment into the computers, peripherals and networking equipment that fill these data centers, which grew by 61% annualized from the previous quarter.

From Barron's ● Feb. 20, 2026

Immediately after the fire took his home, Moore needed to work, but he no longer possessed the peripherals and equipment he required to record.

From Los Angeles Times ● Jan. 7, 2026

On each table there was a different classic home computer or videogame system, accompanied by tiered racks that appeared to hold a complete collection of its peripherals, controllers, software, and games.

From "Ready Player One: A Novel" by Ernest Cline

Related Words

• incidental
• tangential