Dictionary.com
Thesaurus.com
Synonyms

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.


adder 2 American  
[ad-er] / ˈæd ər /

noun

  1. a person or thing that adds.


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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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

Vocabulary lists containing adder

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

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

He found the adder method is more precise, researchers have just misunderstood its true nature.

From Science Daily Apr. 17, 2024

Overall, the adder was thought to result in a less precise size distribution.

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

He had never seen an adder, nor any other type of snake.

From "Redwall" by Brian Jacques

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training