one-tenth; one percent; 3 mm; 2.4 mm; 0.1 degree
Used as a unit meaning one-tenth of various traditional Japanese units: 割 (wari), 寸 (sun), 文 (mon), 度 (do). Context determines the specific unit.
My body temperature rose to 37.5 degrees.
one-quarter of a ryō
Historical currency unit; one bu was one-quarter of a ryō during the Edo period.
advantageous circumstances
Rare usage; refers to a favorable situation or advantage.
He sided with the one who had the advantage.
one-tenth of a monme
Historical unit of weight for silver; one bu is one-tenth of a monme.
See also: 匁 (もんめ)
They measured the weight of silver in units of one bu.
These shoes are size 9 mon 5 bu.
In the Edo period, one bu was one-quarter of a ryō.
分 is one-tenth of a base unit (e.g. 1割の1/10), while 厘 is one-hundredth, so they're easy to mix up when reading old measurements.
The kanji 分 originally means 'part' or 'portion'. The reading ぶ is used for fractional units in traditional Japanese measurement systems.