Originally Posted by lsfreak
Fun fact: the original word isn't adder, it's nadder,
related to Sanskrit (or was it Hindi?) naja, also meaning snake. However, "a nadder" and "an adder" sound the same, and it was reinterpreted from the former to the latter. "A nickname" from "an ekename" is the opposite.
EDIT: Got my etymologies confused. Naga/naja and snake are cognates, not nadder
Did not know about the origins of nickname. Very nice, and makes why nickname means what it does make more sense. Eke (also) + name = ekename (alsoname).