(Greek: retro = backwards, + nym/onuma = name)
A retronym is a word that – due to new meanings of the word in question – needs to stress and point back to the original thing, thus in
analogue wach (not digital) regular coffee (not decaf/decaffeinated) real cream (not a dairy substitute) birth mother (not a surrogate mother, stepmother, or mother-in-law) natural turf (not plastic) acoustic guitar, piano etc. (not electric) a book-book (not an e-book) wood-wood (not plastic imitation) snail mail (not e-mail which is often referred to as just "mail") sugar-sugar (not a sugar substitute)
After decades of worshipping "newness" (and an element of discount substitutes for the real thing) we now seem to feel an urge to return to some of the old, original values, e.g. as in the term "Classic Coke".
After years of "soft serve ice" (which has been proved to be a nesting place for germs) there is now a longing for the uncomplicated old-fashioned ice-cream cone with scoops of ice-cream; in Denmark this is now called "old-fashioned" ice-cream.