quincentennial

[ kwin-sen-ten-ee-uh l ]
/ ˌkwɪn sɛnˈtɛn i əl /

adjective

pertaining to or marking a period of 500 years.

Origin of quincentennial

First recorded in 1880–85; quin(que-) + centennial
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019