box has 6 distinct synonyms spread across 6 of its 13 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is unbox.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a (usually rectangular) container; may have a lid
“he rummaged through a box of spare parts”
Synonyms, antonyms and the broader and narrower relations for box come from Princeton University’s WordNet. Full sources and licences.
private area in a theater or grandstand where a small group can watch the performance
“the royal box was empty”
the quantity contained in a box
“he gave her a box of chocolates”
a predicament from which a skillful or graceful escape is impossible
“his lying got him into a tight corner”
a rectangular drawing
“the flowchart contained many boxes”
any one of several designated areas on a ball field where the batter or catcher or coaches are positioned
“the umpire warned the batter to stay in the batter's box”
separate partitioned area in a public place for a few people
“the sentry stayed in his box to avoid the cold”
a blow with the hand (usually on the ear)
“I gave him a good box on the ear”
engage in a boxing match