Behind the names:

Adidas — from the name of the founder Adolf (Adi) Dassler.

Adobe — came from name of the river Adobe Creek that ran behind the houses of founders John Warnock and Chuck Geschke .

AltaVista — Spanish for "high view".

Amazon — Alternative: It is said that Jeff Bezos named his book store Amazon simply to cash in on the popularity of Yahoo at the time. Yahoo listed entries alphabetically, and thus Amazon would always appear above its competitors in the relevant categories it was listed in.)

Apple — for the favorite fruit of co-founder Steve Jobs and/or for the time he worked at an apple orchard. He was three months late in filing a name for the business, and he threatened to call his company Apple Computer if his colleagues didn't suggest a better name by 5 p.m. Apple's Macintosh is named after a popular variety of apple sold in the US.

Cisco — short for San Francisco. It has also been suggested that it was "CIS-co" -- Computer Information Services was the department at Stanford University that the founders worked in.

Google — the name is an intentional misspelling of the word googol, reflecting the company's mission to organize the immense amount of information available online.

Hotmail — Founder Jack Smith got the idea of accessing e-mail via the web from a computer anywhere in the world. When Sabeer Bhatia came up with the business plan for the mail service, he tried all kinds of names ending in 'mail' and finally settled for Hotmail as it included the letters "HTML" — the markup language used to write web pages. It was initially referred to as HoTMaiL with selective upper casing. (If you click on Hotmail's 'mail' tab, you will still find "HoTMaiL" in the URL.)

Microsoft — coined by Bill Gates to represent the company that was devoted to MICROcomputer SOFTware. Originally christened Micro-Soft, the '-' was removed later on.

Source: http://thekaran.com/iStuff/companyNames.html