There are 2 main definitions of adder in English:

adder1

Line breaks: adder
Pronunciation: /ˈadə
 
/

noun

1A small venomous Eurasian snake which has a dark zigzag pattern on its back and bears live young. It is the only poisonous snake in Britain. Also called viper.
  • Vipera berus, family Viperidae
More example sentences
  • The mating system and spacing pattern of adders largely agree with those of sand lizards.
  • There are also reptiles, like adders or grass snakes, slow-worms and lizards that are prone to fire damage because they cannot get out quickly enough.
  • Along with the loss of heather and cottongrass, birds such as the nightjar, woodlark and stone curlew and animals including the adder, grass snake, and viviparous lizard have been put at risk.
1.1Used in names of snakes that are similar or related to the adder, e.g. death adder, puff adder.
More example sentences
  • A side-winding adder buries itself just beneath the hot sand exposing only its eyes, patiently waiting for unsuspecting prey.
  • The ‘horns’ of his horned adder, resembling a stunning set of false eyelashes, would have drag queens running for cover.

Origin

Old English nædre 'serpent, adder', of Germanic origin; related to Dutch adder and German Natter. The initial n was lost in Middle English by wrong division of a naddre; compare with apron, auger, and umpire.

Definition of adder in:

There are 2 main definitions of adder in English:

adder2

Line breaks: adder
Pronunciation: /ˈadə(r)
 
/

noun

Electronics
A unit which adds together two input variables. A full adder can add a bit carried from another addition as well as the two inputs, whereas a half adder can only add the inputs together.
More example sentences
  • An adder adds the difference and the multiplexed signal and outputs therefrom a driving signal to drive the LD.
  • Further, a semiconductor integrated circuit has a dither pattern generator, an adder, and an error distribution unit.
  • Note that multiplication is done using a SINGLE full bit adder, with the carry bit and output fed back in as feedback loops.

Definition of adder in: