also: うちのかしわでのつかさ
noun
office in charge of the Emperor's meals (ritsuryō system)
Historical term for the imperial kitchen office under the ritsuryō system. Archaic; used only in historical contexts.
内膳司は律令制下で天皇の食事を司った役所である。
The Naizenshi was the office that managed the Emperor's meals under the ritsuryō system.
From 内 (inside, imperial) + 膳 (meal, tray) + 司 (office, director). The reading ないぜんし is Sino-Japanese; うちのかしわでのつかさ is the native Japanese reading.