I just want to spend a few minutes to clarify the difference between these terms. There is some confusion out there and as soon as three people repeat the wrong thing it becomes truth.
Meito: This is a sword with a name (a Gō 号). Any sword can have a name. What we primarily care about this though is a historical name, that is, the blade in question had a name during the Edo period. An example here is the Sunnokina Masamune. It is simply a Masamune that came down through the Edo period with a nickname. This term meito is also used to casually indicate swords of great quality and importance, that may in fact have no name (but we imagine they would be worthy of one). There are no legal restrictions on ownership or movement of meito. Sometimes the NBTHK will indicate a name for a sword in the Juyo or Tokuju papers, in other times it can be discovered through other books or often on the sayagaki where an authority has preserved the name. Sometimes the name comes down with no history at all.
Meibutsu: These are special meito that are on the list of the Kyoho Meibutsu Cho, the most famous swords in the country in Edo period Japan. These also have no restrictions on ownership. However, many of these also happen to be Juyo Bijutsuhin, Juyo Bunkazai and Kokuho and as a result of that kind of status, would be illegal to export from Japan. An example of this would be the Kanze Masamune.
All meibutsu are meito but not all meito are meibutsu.
Utsushi also sometimes take the name of the source blace, for instance Kunihiro coped the Yamanba-giri Chogi, the resulting copy also became famous over the years and so took on a similar name to the original, becoming the Yamanba-giri Kunihiro. Both blades in this situation are meito, but not meibutsu, and both are Juyo Bunkazai making them illegal to export from Japan.