Short answers, pulled from the story.
Sega was founded in 1940 as Standard Games by three American businessmen in Honolulu. The company later evolved into Service Games and eventually adopted the name Sega, which is an abbreviation of Service Games.
Three American businessmen founded the company in 1940 under the name Standard Games. Richard Stewart and Ray LeMare were later sent to Tokyo to establish Service Games of Japan, which became the foundation for what is now known as Sega.
Sega released its first home video game system, the SG-1000, in 1983 alongside the SC-3000 computer. The SG-1000 sold 160,000 units in its first year but was outpaced by Nintendo's Famicom.
Sega announced the discontinuation of the Dreamcast after the 31st of March 2001, and restructured the company as a third-party developer. The final manufactured Dreamcast was autographed by the heads of all nine of Sega's first-party game studios and given away with all 55 first-party Dreamcast games.
Sega announced its merger with Sammy Corporation on the 13th of February 2003, and the deal was completed later that year. In 2004, Sega Sammy Holdings was created as an entertainment conglomerate with Sega and Sammy operating as subsidiaries.