adder

¹ American  

[ad-er] / ˈæd ər /

noun

1. the common European viper, Vipera berus.

2. any of various other venomous or harmless snakes resembling the viper.

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adder ² American  

[ad-er] / ˈæd ər /

noun

1. a person or thing that adds.

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adder ¹ British  

/ ˈædə /

noun

1. Also called: viper.  a common viper, Vipera berus, that is widely distributed in Europe, including Britain, and Asia and is typically dark greyish in colour with a black zigzag pattern along the back

2. any of various similar venomous or nonvenomous snakes

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adder ² British  

/ ˈædə /

noun

1. a person or thing that adds, esp a single element of an electronic computer, the function of which is to add a single digit of each of two inputs

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Etymology

Origin of adder¹

before 950; late Middle English; replacing Middle English nadder ( a nadder becoming an adder by misdivision; cf. apron), Old English næddre; cognate with Old Saxon nādra, Old High German nātara ( German Natter ), Old Norse nathra snake, Gothic nadrs adder, Old Irish nathir snake, Latin natrix water snake

Origin of adder²

First recorded in 1570–80; add + -er ¹

Example Sentences

The vet found a small mark but no swelling, which is a common symptom of an adder bite, so was unable to confirm it was the cause.

From BBC • Apr. 24, 2026

When ElGamel took the number of molecules into account alongside the additional mass, the adder strategy was more precise and less sensitive to mistakes during replication.

From Science Daily • Apr. 17, 2024

But if something goes wrong using the so-called adder strategy, the cell takes longer to get back to its original size.

From Science Daily • Apr. 17, 2024

To investigate, Ms. Folwell set about dissecting the tail of a female death adder.

From New York Times • Dec. 13, 2022

Nervously, she told him about the dead Portuguese and the panga she thought he had given her, about the puff adder that had come from the ancestors, and about Long Teats.

From "A Girl Named Disaster" by Nancy Farmer

Related Words

• cobra