The species of nettle we’re talking about here is Urtica dioica. The Urtica part is a direct borrowing from the Latin urtīca, ‘nettle’, which in turn is from ūrere, ‘to burn’. That makes sense. Ouch! Nettles do make your skin feel as if it’s burning. And that burning is expressed in the prefix to the Danish word for stinging nettles, brændenælder, Danish using the same verb for ‘to burn’ and ‘to sting’. That same Latin word urtīca is also the root of the technical name for nettle rash, urticaria.