Meaning

noun a person who adds numbers

noun a machine that adds numbers

noun small terrestrial viper common in northern Eurasia

originFrom Middle English nadder, addere, rebracketing of “a naddere” as “an addere”, from Old English nǣdre (“snake”), from Proto-West Germanic *nadrā, from Proto-Germanic *nadrǭ, from pre-Germanic *néh₁treh₂, variant of Proto-Indo-European *n̥h₁trih₂, from *(s)neh₁- (“to spin, twist”). See also West Frisian njirre, Dutch adder, German Natter, Otter; also Welsh neidr, Latin natrīx (“watersnake”),…

Etymology from Wiktionary, CC BY-SA 3.0