Vaporware
A product, typically computer hardware or software, that is announced to the general public but is never actually manufactured nor officially cancelled.
Origin
A Microsoft engineer coined the term in 1982 while discussing the stalled Xenix operating system with software executive Ann Winblad. Technology journalist Esther Dyson published and popularized the word in her influential newsletter RELease 1.0 in November 1983, defining it as "good ideas incompletely implemented." The term gained wider fame when journalist Stewart Alsop gave Bill Gates a "Golden Vaporware" award after Windows shipped eighteen months late in 1985.
Everyday Use
Ever get excited about a product announcement only to hear nothing about it again for years? That's vaporware. Tech companies sometimes announce products early — to gauge interest, freeze competitors, or simply because they're overly optimistic about timelines. The product lives in a limbo between "coming soon" and "quietly forgotten."