noun
back body panel of a kimono
Refers specifically to the back piece of a kimono or similar traditional garment, as opposed to the front panel (前身頃).
着物の後ろ身頃に刺繍を施す。
Embroider the back body panel of the kimono.
前身頃 is the front body panel, while 後ろ身頃 is the back body panel.
Compound of 後ろ (ushiro, 'back') + 身頃 (migoro, 'body panel of a garment').