If you have ever second-guessed yourself on what the plural form of radius was and also wanted to learn more about the word, it’s grammar, it’s history, and plenty of examples of it used in a sentence, this article is practically made for you!
What Is the Definition of Radius?
According to Merriam-Webster.com, the word radius has these definitions and uses.
- a line segment extending from the center of a circle or sphere to the circumference or bounding surface
- the bone on the thumb side of the human forearm next to the ulna
- also: a corresponding part of vertebrates above fishes
- the third and usually largest vein of an insect’s forelimb
- the length of a radius
- a truck with a short turning radius
- the circular area defined by a stated radius
- a bounded or circumscribed area
- a radial part
- the distance from a center line or central point to an axis of rotation
- the length of this line is called the radius
What Is the Difference Between Radius and Radi?
Radius is the singular form and one of the plural forms of the word radius is radii. So if you are referring to the radius of two objects or more then you could say “the radii of the two objects”.
There is also the plural form more common for conventional English speakers radiuses. Depending on whether or not you are using it in a formal sense, like a paper or homework, you can use either plural form. The more accepted plural form of the word is radiuses, based on the Latin plural.
The History and Origin of the Word
The word radius has an origin dating back to 1578. It was used in the context of the first definition listed above “a line segment extending from the center of a circle or sphere to the circumference or bounding surface”.
The word radius can be traced back to the Latin language. It is a word borrowed from the Latin radius and used in the same spelling and context today in American English. The definition in Latin is staff, spoke, ray, spoke of a wheel, ray of light, beam of light, radius of a circle. First used for geometry in the 1610s.
Example Sentences of the Word in Context
- Restaurant delivery is free within a three-mile radius and $8 within five miles. — Tom Sietsema, Washington Post, “These three restaurants can help you keep date night on your to-do list,” 21 Aug. 2020
- Mosquito control ground spraying will happen within a one mile radius of the following locations. — Mary Grace Granados, Dallas News, “Grapevine will continue mosquito spraying this weekend,” 20 Aug. 2020
- In 2018 Harris and Abdulhadi had approached SZA to play their Portland, Oregon festival, but were turned down because of the terms of Coachella’s radius clause. — Dave Brooks, Billboard, “Coachella Radius Clause Lawsuit Moving Ahead After All,” 19 Aug. 2020
- Also, many of our customers live outside the 5-mile radius limit that most of the delivery services offer. — Lennie Omalza, The Courier-Journal, “Louisville’s Asian-fusion restaurants see light at the end of the tunnel amid the pandemic,” 19 Aug. 2020
- Local means the distance that a bee travels to get pollen, which is about a 6-mile radius. — Emily Hilton, The Hollywood Reporter, “Amid Pandemic, Chris Hemsworth, Sophia Bush and More Turn to Beekeeping: “It’s the Most Calming Experience”,” 15 Aug. 2020
- It’s got a 30-foot cord, a six-foot six-inch hose, and a telescoping extension wand that together provide for a 40-foot cleaning radius. — Sarah Bogdan, Good Housekeeping, “8 Best Canister Vacuums of 2020, According to Cleaning Experts,” 5 Aug. 2020
- The only utility of this fire is to sear the memory of an awesome week at camp into the brain of every person within a quarter-mile radius. — T. Edward Nickens, Field & Stream, “Wild Fires,” 9 Jan. 2017
- Delivery just at Colonnade location for an additional $3.95 within a 5-mile radius of the restaurant, or through GrubHub. — Chuck Blount, ExpressNews.com, “52 Weeks of Pizza: Goomba’s Pizzeria restaurant in San Antonio still delivers classic New York-style pizza,” 7 Aug. 2020
Synonyms of Radius from the Thesaurus
- Area – region or part of a town, country, or the world
- Bounds – a figurative limit
- Circle – something in the shape of a circle
- Range – maximum distance of capability
- Remit – to transmit, supply or send, especially money or payment
- Scope – the extent of the area or subject matter that something deals with or to which it is relevant
- Sweep – to brush off or brush away, typically dirt or litter, to art or turn away from a straight line or course
- Umbrella – a device consisting of a circular canopy of cloth on a folding metal frame supported by a central rod, used as protection against rain
- Ambit – the action or process of enlarging or extending something
- Area of influence – range, sweep, area or sphere of activity regarded as someone’s personal territory
- Boundary – outside limit of an object, area or surface
- Compass – range or scope of something
- Expanse – a wide stretch, usually of sea, sky, or land
- Spoke – spoke of a tire
Now you are no doubt an expert on using the correct plural form of the word radius in the English language and hopefully also took away a lot more about the word. Next time you are writing a paper or doing your homework you can confidently use the correct plural form.