adder

/AE1 D ER0/
noun
  1. 1

    Any snake.

  2. 2

    A name loosely applied to various snakes more or less resembling the viper; a viper.

noun
  1. 1

    Someone who or something which performs arithmetic addition; a machine for adding numbers.

  2. 2

    An electronic device that adds voltages, currents or frequencies.

  3. 3

    Something which adds or increases.

    โ€œThey sought out cost adders with an eye toward eliminating them.โ€

Source: https://en.wiktionary.org/wiki/adder