octocentenary

[ ok-toh-sen-ten-uh-ree, -sen-tn-er-ee or, esp. British, -sen-tee-nuh-ree ]
/ ˌɒk toʊ sɛnˈtɛn ə ri, -ˈsɛn tnˌɛr i or, esp. British, -sɛnˈti nə ri /

adjective

pertaining to 800 or a period of 800 years; marking the completion of 800 years.

noun, plural oc·to·cen·ten·ar·ies.

an 800th anniversary or its celebration.

Origin of octocentenary

First recorded in 1885–90; octo- + centenary

British Dictionary definitions for octocentenary

octocentenary
/ (ˌɒktəʊsɛnˈtiːnərɪ) /

noun plural -naries

an eight-hundredth anniversary