Illustration of adder
- adder 1
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
: one that adds
especially
: a device (as in a computer) that performs addition
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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
Stories By Real-Time News Team, With Ai Summarization, Miami Herald, 28 Mar. 2025
The 2024 photo, however, clearly showed a Vipera berus, also known as the common European adder or common European viper, on Sylt Island, the study said.
—Aspen Pflughoeft, Miami Herald, 21 Mar. 2025
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
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Noun
See it On Sylt Island in northern Germany, a resident’s photograph confirmed the presence of a Vipera berus, also known as the common European adder.
—Stories By Real-Time News Team, With Ai Summarization, Miami Herald, 28 Mar. 2025
The 2024 photo, however, clearly showed a Vipera berus, also known as the common European adder or common European viper, on Sylt Island, the study said.
—Aspen Pflughoeft, Miami Herald, 21 Mar. 2025
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
Cite this Entry
“Adder.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/adder. Accessed 10 Jul. 2025.
Copy CitationKids Definition
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
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