分区 is read as ぶんく (bunku) and means subdistrict.
ぶんく
bunku
くぶん
division
くわけ
じだいくぶん
division of history into periods
しじょうくぶん
market segment
くぶんふぁいる
partitioned file
くぶんてき
piecewise
おーばれいくぶん
overlay (segment)
くぶんでーたせっと
partitioned data set
とりひきくぶん
transaction classification
くぶんたてもの
building consisting of individually owned units, shops, etc.
くぶんしょゆうたてもの
くぶんしょゆうけん
unit ownership (in a condominium or other multi-unit building)