Not wanting to be too persnickety, but...
The word is "biennial" - every two years, not biannual - twice per year. From an FAA perspective, the preferred term is "Flight Review." It ceased being the BFR sometime late last century.
Background - in the mid/late '90s the FAA considered having a flight review for pilots with less than 400 hours every 12 calendar months and one for more experienced pilots every 24 calendar months. Since it was no longer "biennial" for everyone the term "flight review" was adopted. Twenty years ago...
Terry