As a Nelda, I have researched my name numerous times and found it is also a short name for Elenore. I was named after a Puerto Rican woman that was my mother's neighbor in Texas. It also has the form of being Nilda in Spanish and Latin American usage. To me it has always been the name of an old woman and as I age, I find this to be true and tend to hear it more and more lately, even on commercials. Growing up with this name was no picnic and I must admit, I find Zelda a better and more suited name than Nelda. Just my opinion.
I think of this name as being softer & gentler than Zelda, but just as cool. Maybe it's because I'm reminded of words like "nestle" and "nest" that I find it sweeter. It's got an antique, old lady charm, sophisticated yet quirky. Lovvve it!