brian whatcott wrote
It's interesting that the COD can distinguish biennial from biannual,

It dosen't matter....biennial or biannual, they and the abreviation BFR
are all incorrect. The FAA makes a big difference between "every two
years" and "since the beginning of the 24th calendar month......".
The FAA has not used "BFR" since about 1995 as I recall.

FAR Section 61.56
61.56 Flight Review......
(c) Except as provided in paragraphs (d), (e) and (g)
of this section, no person may act as pilot in command
of an aircraft unless, since the beginning of
the 24th calendar month before the month in
which that pilot acts as pilot in command, that
person has—
(1) Accomplished a flight review given in an aircraft
for which that pilot is rated by an authorized
instructor; and
(2) A logbook endorsed from an authorized
instructor who gave the review certifying that
the person has satisfactorily completed the
review.

Bob Moore
Holder of an FAA Flight Instructor certificate
NOT a CFI