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：septi-, sept-, septem-

【来源及含义】Latin: seven, seventh; a word element for number 7

【同源单词】septangle, septangular, septarch, septarchy, septave, September