suburban districts of a metropolis; within an urban prefecture
Refers to the area under the jurisdiction of a 府 (urban prefecture), such as Osaka or Kyoto. Often used in administrative or geographical contexts.
大阪府下の市町村を調査した。
We surveyed the municipalities within Osaka Prefecture.
府下全域に警
A warning was issued for the entire prefectural area.
Compound of 府 (urban prefecture) and 下 (under, within). The reading ふか is a standard on'yomi combination.