noun
jūbako; multi-tiered food box
A traditional Japanese lacquered container with stacked compartments, used for serving food on special occasions such as New Year's.
お正月には、重箱におせち料理を詰めます。
For New Year's, we pack osechi dishes into a jūbako.
Compound of 重 (jū, 'stacked' or 'layered') and 箱 (hako, 'box'), with rendaku voicing hako → bako. The reading じゅう is the on'yomi of 重.