adder

/ˈædər/
noun
  1. A small poisonous snake found in Europe and parts of Asia, often with a zigzag pattern on its back.
    • Adders usually avoid humans and will only bite if threatened.
    • We saw an adder sunning itself on a rock during our hike.
    • The common adder is the only venomous snake native to the United Kingdom.
  2. A person or thing that adds something, especially numbers.
    • The cashier was a quick adder and rarely made mistakes.
    • She's a fast adder and finished the math test early.
    • This machine is a reliable adder for basic arithmetic.
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