biennial /bī-enˈi-əl or -enˈyəl/

1. Lasting two years
2. Happening or appearing once in two years

1. A plant that flowers and fruits only in its second year, then dies
2. An event taking place or being celebrated every two years

biennˈially adverb

• musteline
• mustelines
• muster
• muster book
• muster books
• mustered
• musterer
• musterers
• muster-file
• muster-files
• muster in
• mustering
• muster-master
• muster-masters
• muster out
• muster roll
• muster rolls
• musters
• musth
• must-have
• must-haves
• musths
• mustier
• mustiest
• mustily