Definition of "centenarian"

The average age of these 203 centenarians was 102 years 5 months and 25 days.

1894 October 19, “Sex and Long Life”, in Public Opinion: A Comprehensive Summary of the Press Throughout the World on All Important Current Topics, volume LXVI, number 1,726, London

He proposed the formation of the Louisiana Live Oak Association, whose members would be trees at least a hundred years old. First among the centenarians he listed was the Locke Breaux oak, the largest tree he knew, measuring 10.7 m (35 ft.) in circumference, 22.8 m (75 ft.) tall, with a spread of 50.6 m (166 ft.) in 1932.

2003, Kit Anderson, Nature, Culture, and Big Old Trees: Live Oaks and Ceibas in the Landscapes of Louisiana and Guatemala, University of Texas Press, page 136