adder

from The Century Dictionary.

• noun The popular English name of the viper, Vipera communis, now Pelias berus, a common venomous serpent of Europe (and the only poisonous British reptile), belonging to the family Viperidæ, of the suborder Solenoglypha, of the order Ophidia.
• noun A name loosely applied to various snakes more or less resembling the viper, Pelias berus: as
• noun The sea-stickleback or adder-fish. See adder-fish.
• noun One who adds.
• noun An instrument for performing addition.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who, or that which, adds; esp., a machine for adding numbers.
• noun obsolete A serpent.
• noun A small venomous serpent of the genus Vipera. The common European adder is the Vipera berus or Pelias berus. The puff adders of Africa are species of Clotho.
• noun In America, the term is commonly applied to several harmless snakes, as the milk adder, puffing adder, etc.
• noun Same as Sea Adder.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Someone who or something which performs arithmetic addition.
• noun Something which adds or increases.
• noun obsolete A snake.
• noun A name loosely applied to various snakes more or less resembling the viper; a viper.
• noun chiefly UK A small venomous serpent of the genus Vipera. The common European adder is the Vipera berus. The puff adders of Africa are species of the genus Oecobius.
• noun US, Canada Any of several small nonvenomous snakes resembling the adder, such as the milk snake.
• noun The sea-stickleback or adder-fish.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a machine that adds numbers
• noun a person who adds numbers
• noun small terrestrial viper common in northern Eurasia