- Daewoo – company founder Kim Woo Chong called it Daewoo which means "Great House" or "Great Universe" in Korean.
- DAF Trucks – from 1932 the company's name was Van Doorne's Aanhangwagen Fabriek (Van Doorne's Trailer Factory). In 1949 the company started making trucks, trailers and buses and changed the name into Van Doorne's Automobiel Fabriek (Van Doorne's Automobile Factory).
- Daihatsu – the first kanji from "Osaka" (大坂, the kanji is here pronounced dai) and "engine" (発動機, the first kanji is hatsu). Engine manufacturers were listed on the Tokyo and Osaka Stock Exchanges, and their names shortened to the first kanji. (The company listed on the Tokyo exchange is Tohatsu.)
- Danone (Dannon in the U.S.) – Isaac Carasso in Barcelona made his first yogurts with the nickname of his first son Daniel (DAN-ONE)
- Datsun – first called DAT, from the initials of its financiers Den, Aoyama and Takeuchi. Soon changed to DATSON to imply a smaller version of their original car, then (as SON can mean "loss" in Japanese) again to DATSUN when they were acquired by Nissan.
- Debian – project founder Ian Murdock named it after himself and his girlfriend, Debra.
- DEC – Digital Equipment Corporation, a pioneering American minicomputer manufacturer founded by Ken Olsen and taken over by Compaq, before Compaq was merged into Hewlett-Packard (HP). It was generally called DEC ("deck"), but later tried to rebrand itself as Digital.
- DEKA – named after its founder Dean Kamen, developer of the Segway, iBOT, HomeChoice Dialysis and other products.
- Delhaize – named after its founders, Jules Delhaize and his brothers, who originated from Charleroi (Belgium). They opened the first European self-service "supermarket" in Ixelles/Elsene, a Brussels borough.
- Dell – named after its founder, Michael Dell. The company changed its name from Dell Computer in 2003.
- Denning & Fourcade, Inc. – interior designer company named after its founders Robert Denning and Vincent Fourcade in 1960.
- DHL – named after its founders, Adrian Dalsey, Larry Hillblom, and Robert Lynn.
- Dick's Sporting Goods – named after its founder, Dick Stack, who opened a bait and tackle shop in 1948 with a $300 gift from his grandmother.
- Digg, Inc.- Kevin Rose's friend David Prager (The Screen Savers, This Week in Tech) originally wanted to call the site "Diggnation", but Kevin wanted a simpler name. He chose the name "Digg", because users are able to "dig" stories, out of those submitted, up to the front page. The site was called "Digg" instead of "Dig" because the domain name "dig.com" was previously registered, by Walt Disney Internet Group. "Diggnation" would eventually be used as the title of Kevin Rose and Alex Albrecht's weekly podcast discussing popular stories from Digg.
- Digi-Key – electronic component distributor whose name is derived from founder Dr. Ronald Stordahl's amateur radio telegraphic keyer, the "IC Keyer Kit", which utilized digital integrated circuits.
- The Walt Disney Company, named for its co-founder Walt Disney.
- Dixons – commonly used abbreviation for DSG International plc (Dixons Stores Group), a UK-based retailer. The company was founded in 1937 by Charles Kalms and Michael Mindel. When opening their first photographic shop in Southend, they only had room for six letters on the fascia, and chose the name Dixons from the phone book.
- DKNY – Donna Karan New York.
- Dow – named after its founder, Herbert Henry Dow.
- DSM - established in 1902 to exploit the Dutch coal mines, the name meaning Dutch State Mines. The last mine closed in 1973, and the company switched to chemicals.
- Duane Reade – named after Duane and Reade Streets in lower Manhattan, where the chain's first warehouse was located. The chain was purchased by Walgreens in 2010, but still operates separately.
- DuPont – short name for E. I. du Pont de Nemours and Company. This American chemical company was founded in 1802 as a gunpowder mill by Eleuthère Irénée du Pont, who left France to escape the French Revolution.
- Dynegy – the Natural Gas Clearinghouse changed its name in 1998 to reflect its self-described traits as a dynamic energy company. "Dynergy" had already been taken by a German health foods company.
Read more about this topic: List Of Company Name Etymologies