jubilarian

jubilarian \joo-buh-LAIR-ee-uhn\, noun:

A person who celebrates or has celebrated a jubilee, as a nun observing 25 or more years of religious life.

To enable the school to open in 1916, Sisters Agnes Geraghty and Corona Hargrafen, golden jubilarians, had come out of retirement, and Sister Juliana Kritenbrink, another golden jubilarian, joined them the next year.
-- O. P. Dolores Enderle, Suzanne Noffke, The Dominicans of Racine, Wisconsin

The crowd was so great that when the doors were closed at a late hour to relieve the strain on the seventy-two-year-old jubilarian, a line of people still reached around the south and west sides of the Square.
-- Patrick Ryan, Archbishop Patrick John Ryan His Life and Times

In Biblical tradition, the jubilee is a yearlong celebration which occurs every 50 years. All debts are forgiven and lands returned to their original owners. Today jubilees are often celebrations of significant anniversaries, particularly every 25, 50, 60 or 75 years. Jubliarian refers to anyone who has or is celebrating a significant 25-year milestone.