An adder used to be called a nadder!
The Old English word for adder was nǣdre, which became nadder in Middle English. By the mid-1400s, the word was being spelled both with and without the n, but since about 1500, without the n has prevailed
Linguists call it a false division or a misdivision; at some point the spelling or sound of the word was split in the wrong place and the new word went off by itself without its initial letter.
Should the park’s adders go back to being nadders, do you think?
Header picture by Benny Trapp (CC-BY-3.0)