adder

IPA/ˈadə/
KK[ˈædɚ]IPA/ˈædər/

adder — noun

1. a small viper found in Europe and northern Asia that carries venom and can bite

1.nounB2
Definition

a small viper found in Europe and northern Asia that carries venom and can bite in self-defence; in Britain, it is the only snake native to the country that can inject venom.

Example

Indra spotted an adder warming itself on a flat rock by the path.

wildlife encounter: adder warming itself on a rock

Park workers warned hikers that adders sometimes hide in long grass.

Common collocations
  • adder bite
  • adder habitat
  • adder population
  • female adder
Synonyms
  • viper

    broader family term; an adder is one kind of viper, not the whole group

  • common viper

    formal wildlife name for the same European species

Grammar Patterns

an/the + adder

Usage Note

Usually refers to the European adder, especially in British writing about wildlife. People often mention its dark zigzag back markings when they are trying to identify it outdoors.

Common Mistakes

Every adder in Britain attacks people.
Adders usually avoid people and bite mainly when disturbed.
The snake is venomous, but it does not normally chase or hunt humans.

adder — noun

1. a machine or computer part that adds numbers together to produce a total.

1.nounC1
Definition

a machine or computer part that adds numbers together to produce a total.

Example

The old shop kept a hand-cranked adder beside the cash drawer.

older office machine: hand-cranked adder

This tiny adder on the chip can combine two numbers at once.

computing use: adder on a chip

Common collocations
  • binary adder
  • full adder
  • electronic adder
  • hand-cranked adder
Synonyms
  • adding machine

    older term for a device used to do addition, especially in shops or offices

  • calculator

    more common and broader; a calculator usually does more than addition

Grammar Patterns

an/the + adder

adder + for + numbers

Usage Note

Most often appears in technical contexts, especially older office equipment and computer hardware. In everyday English, people are more likely to say 'calculator' or use a more specific hardware term.

Common Mistakes

My phone is just an adder.
My phone has an adder inside it, but it does much more than add numbers.
An adder only performs addition, while a phone or full calculator has many other functions.

2. someone who adds numbers, especially quickly or accurately.

2.nounC2
Definition

someone who adds numbers, especially quickly or accurately.

Example

In the maths relay, Sophia was the quickest adder on her team.

person noun: quickest adder on a team

The teacher asked the best adder in each pair to check the final sum.

Common collocations
  • quick adder
  • accurate adder
  • skilled adder
  • adder of numbers
Synonyms
  • calculator

    when used of a person, this means someone who works things out carefully, not only someone who does addition

  • mental-maths star

    informal phrase for a person who adds and calculates very quickly

Grammar Patterns

an + adder

adder of + numbers

Usage Note

This personal sense is rare and usually appears in teaching or contest contexts. Outside those settings, speakers normally say 'someone who is good at maths' or describe the person's speed directly.

Common Mistakes

She is an adder because she studies maths.
She is a strong adder because she can add long columns quickly.
The word describes someone actually doing addition well, not simply anyone who learns mathematics.

Synonym discussion

Sense: noun/1

In British wildlife writing, 'adder' usually means the European adder, the small venomous snake also called the common viper. 'Viper' is the broader biological label for the whole family, so every adder is a viper, but many vipers are not adders. 'Cobra' names a different kind of venomous snake with a hood and a very different body shape, so it should not be used as a synonym for adder. 'Grass snake' is another British snake, but it is non-venomous and usually slimmer and longer than an adder. If you are talking about the specific British species, choose 'adder'; if you mean the wider family, use 'viper'.

viper ↗cobra ↗grass snake

Etymology

Old EnglishMiddle EnglishEnglish

Modern English 'adder' actually brings together two different histories. The snake word comes from Old English 'næddre', which later changed shape when speakers redivided the phrase 'a nadder' as 'an adder'. The arithmetic word is much newer: it was formed inside English from the verb 'add' plus the ending '-er', first for a person who adds and later for machines and computer parts. So the snake sense and the arithmetic senses share a spelling today, but they do not come from the same root.