also: さんぱこ · みはこ · さんばこ
noun
three boxes; three box-shaped things; three containers
Counter for boxes, cases, or box-like objects. The reading さんはこ is the most standard.
引っ越しの荷物は三箱だけだった。
The moving luggage was only three boxes.
このお菓子を三箱ください。
Please give me three boxes of these sweets.