Other forms: supercentenarians
Is your great grandfather 112 years old? If so, he's a supercentenarian, a person who has been alive for more than 110 years.
You don't see supercentenarian as much as you see the word it's based on, centenarian, "person who's 100 or older." That's probably because it's extremely rare for anyone to live beyond the age of 110. There may be as many as 150 supercentenarians worldwide, although some experts are dubious that this many people are really as elderly as they claim to be. The word derives from the Latin centum, "hundred," and the prefix super-, "beyond."