Nintendo is one of the best-known company names on earth, and nobody knows for sure what it means.
The company began on 23 September 1889 in Kyoto. Its founder, Fusajiro Yamauchi, made hanafuda, Japanese "flower cards" used for games. Wikipedia notes that Japan had banned most forms of gambling in 1882 but tolerated hanafuda. The first name was Nintendo Koppai. The business was soon known as Yamauchi Nintendo.
The standard translation is "leave luck to heaven." It is repeated so often that it reads like a fact. Wikipedia's history of the company says plainly that there are no historical records to confirm it.
The name is written with three characters, 任天堂. The middle one means sky or heaven, and the last two together read as tendō, "heaven" or "paradise." The first one, nin, is the puzzle. Kotaku reports that the authors Florent Gorges and Isao Yamazaki read it as "let someone do." On that reading, Nintendo could mean something like "the company allowed to sell hanafuda." Kotaku also reports a more colorful claim, from the journalist Jake Adelstein, that yakuza members link nin to ninkyo, "chivalry."
None of these can be settled. Kotaku says Hiroshi Yamauchi, described as the founder's great-grandson, called "leave luck to heaven" a plausible explanation. He also admitted he did not know the true meaning. The founder left no explanation behind.
The name changed shape several times before it settled. Wikipedia lists Yamauchi Nintendo & Co. from 1933, Marufuku Co. from 1947, and Nintendo Playing Card Co. from 1951. In 1963 the words "playing card" were dropped. That last change fit a company looking beyond cards.
It looked in odd directions. In 1960 Nintendo ran a Kyoto taxi company called Daiya Taxi. It also sold instant rice and made a vacuum cleaner. A popular story adds love hotels to that list. Wikipedia reports that Nintendo's securities reports and other records of the time do not support it.
The video games arrived late. In 1977 Nintendo released the Color TV-Game consoles, developed with Mitsubishi Electric. A card maker named, perhaps, for trusting luck to heaven had found its real business nearly 90 years in.