"done or recurring every ninth year," 1650s, from Latin novennialis, from novennis "of nine years," from novem "nine" (see nine) + annus "year" (see annual (adj.)).
Entries linking to novennial
nine adj., n.
"the cardinal number one more than eight or one less than ten; the number which is one more than eight;" Middle English nīn, from Old English nigen, from Proto-Germanic *newun (source also of Old Saxon nigun, Old Frisian niugun, Old Norse niu, Swedish nio, Middle Dutch neghen, Dutch negen, Old High German niun, German neun, Gothic niun "nine").
This is from PIE root *newn "nine" (source also of Sanskrit nava, Avestan nava, Greek ennea (with unetymological initial e-), Albanian nende, Latin novem (with change of -n- to -m- by analogy of septem, decem), Lithuanian devyni, Old Church Slavonic deveti (the Balto-Slavic forms by dissimilation of -n- to -d-), Old Irish noin, Welsh naw).
As "a symbol representing the number nine," late 14c. The proverbial nine lives of a cat are attested from 17c. Nine-to-five "the average workday" is attested from 1935. Nine days (or nights) has been proverbial since mid-14c. for the time which a wonder or novelty holds attention; the expression nine days' wonder is from 1590s. The Nine "the Muses" is from c. 1600. Also see nines.
annual adj.
late 14c., "appointed by the year;" c. 1400, "occurring or done once a year," from Old French annuel "yearly" (12c.) or directly from Medieval Latin annualis "yearly," corresponding to Latin annalis as adjective form of annus "year."
This is reconstructed to be from Proto-Italic *atno- "year" (compare Oscan akno- "year, holiday, time of offering"), from PIE *at-no- "which goes," also "a year" (as "going around"), suffixed form of root *at- "to go" (source also of Sanskrit atati "goes, wanders," atamana- "to travel, wander," atya- "steed, runner"). The root also has Germanic derivatives meaning "a year," such as Gothic aþnam (dative plural) "year."