词根词缀：-enni-, -ennial, -ennium
【来源及含义】Latin: year, years
【同源单词】aere perennius, amillennialism, annual, biannual, bicentennial, biennia
词根词缀：tri-, tre-
【来源及含义】Greek > Latin: a numerical prefix meaning, three, thrice, threefold; triple; a word element for number 3
【相关词根词缀】 Cross references of word families that are related, partially or totally, to: "three, third": terce-; terti-; trigono-; trito-.