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：octa-, octo-, oct-, octi-, octon-

【来源及含义】Greek > Latin: eight, eighth

【同源单词】octachord, octad, octagon, octagonal, octagynous, octahedral