As a denizen of the Emerald City, the Name Inspector has been intrigued by the meteoric rise of the online real estate service Zillow, and has speculated on the origins of their name. Those speculations, though enjoyable, have turned out to be pointless, because it says right there on their website how they came up with the name. Zillow is a blend (or, to be old-fashioned and French about it, a portmanteau) of zillions (as in “zillions of data points”) and pillow (a metonymic reference to home–where you rest your head).
Because blend names are based on real words, they often have a familiar ring to them. They can be especially seamless and elegant when, as in this name, they overlap through rhyming syllables.
Zillow adds an unusual first letter and sound z to an unusual and especially mellow-sounding word ending -illow. The only common two-syllable words that the Name Inspector can think of right now that share that ending are pillow, willow, and billow. Willow regularly shows up on lists of the most beautiful-sounding English words. Two qualities that make it beautiful are its symmetry (beginning and ending with w) and its high sonority (that is, its lack of sounds that obstruct the flow of air through the vocal tract). Both qualities are diminished when the z replaces the w, but the name still sounds pretty good. The Z is distinctive, but the company goes overboard applying it to other names for specific services: Zillow alone says “cool”, but Zindex and Zestimate tagging along say “zzz”.
Because both zill- and -illow are unusual word-halves and don’t evoke many competing meanings, Zillow brings to mind zillion and pillow surprisingly well. Even if you don’t get the “right” association for -illow, you’re bound to get an appropriate one: willow suggests yards or gardens, and billow suggests sailboats and, by association, wealth. Not bad.