adder

1 of 2

noun (1)

ad·​der ˈa-dər 

1

: the common venomous viper (Vipera berus) of Europe

broadly : any of various snakes of the viper family compare puff adder

2

: any of several North American snakes (such as the hognose snakes) that are harmless but are popularly believed to be venomous

Illustration of adder

• adder 1

adder

2 of 2

noun (2)

add·​er ˈa-dər 

: one that adds

especially : a device (as in a computer) that performs addition

Did you know?

How Adder Lost Its First Letter

Words formed by what linguists call “false division,” “misdivision,” or “metanalysis” have spellings that record a mistake that was made at some point in their history, when the spelling or sound of the word was split in the wrong place.

Misdivisions of words that begin with the letter n are frequent because, in speech, it is difficult to distinguish between the sound of the indefinite article “a” followed by a word beginning with an n (as in “a name”) and the sound of the indefinite article “an” followed by a word beginning with a vowel (as in “an aim”). This make the position of the n very easily confused.

An example is the name of the venomous snake known as the adder. The Old English word for this viper was nǣdre, which became nadder in Middle English. Over time, a nadder became an adder. By by the mid-1400s, the word was being spelled both with and without the n, but since about 1500, the n-less spelling has prevailed.

Examples of adder in a Sentence

Recent Examples on the Web

Noun

The death adder’s plight illustrates another important point: In a 2013 review of the relevant scientific literature to date, Robertson and his colleagues concluded that exotic species are the single largest cause of evolutionary traps. —Cody Cottier, Discover Magazine, 30 Sep. 2024

This attitude poses a threat to Europe’s adder populations, already on the decline because of habitat destruction. —Byphie Jacobs, science.org, 20 Sep. 2024

That massive range is in part due to the adder’s ability to withstand low temperatures, Lüddecke explains. —Byphie Jacobs, science.org, 20 Sep. 2024

Sometimes referred to as the Gaboon adder, this snake preys on a variety of small to medium-sized animals, including rodents like rats, birds such as francolins, and small mammals like rabbits and mongooses. —Scott Travers, Forbes, 7 Sep. 2024

Known by a host of common names—trout lily, fawn lily, and adder's tongue—this woodland wildflower is a harbinger of spring. —Nadia Hassani, Better Homes & Gardens, 31 Jan. 2024

The Australian death adder spends most of its days hidden in leaf litter, often with only the tip of its tail exposed. —Elizabeth Kolbert, The New Yorker, 27 Mar. 2023

Biologists found that death adders possess clitorises, then went on to locate them in eight other species of snakes. —Matthew Gavin Frank, Harper's Magazine, 21 Mar. 2023

Australian scientists who played sounds for snakes found that woma pythons tend to move toward pink noise while death adders tend to move away. —Michael W. Clune, Harper’s Magazine , 10 Apr. 2023

Word History

Etymology

Noun (1)

Middle English addre, eddre, alteration (resulting from misdivision of a naddre) of naddre, neddre, going back to Old English nǣdre "adder, snake," going back to West Germanic nēdrōn- (whence also Old Saxon nādra "grass snake [Natrix natrix or allied species]," Old High German nātara, nāter), going back to dialectal (western) Indo-European *neh₁tr-, full-grade ablaut of *nh₁tr- (whence Old Norse naðr "adder, snake," Gothic nadrs "snake, viper," Latin natric-, natrix "water snake [as Natrix maura]," Old Irish nathir [genitive singular nathrach] "snake," Welsh neidr [plural nadredd], Breton aer, naer "grass snake"), perhaps from *(s)neh₁- "twist together, spin" + *-tr-, -ter-, agent suffix (hence "one who winds, twists") — more at needle entry 1

Noun (2)

add + -er entry 2

First Known Use

Noun (1)

14th century, in the meaning defined at sense 1

Noun (2)

1547, in the meaning defined above

Phrases Containing adder

• adder's-tongue
• puff adder

Kids Definition

adder

1 of 2 noun

ad·​der ˈad-ər 

1

: a poisonous European viper

also : any of several related snakes

2

: any of several harmless North American snakes (as the hognose snakes)

adder

2 of 2 noun

add·​er ˈad-ər 

: one that adds

Medical Definition

adder

noun

ad·​der ˈad-ər 

1

: the common venomous European viper of the genus Vipera (V. berus)

broadly : a terrestrial viper of the family Viperidae

2

: any of several North American snakes (as the hognose snakes) that are harmless but are popularly believed to be venomous