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general::
Phrase(s): pack something down
to make something more compact; to press something in a container down so it takes less space. • The traffic packed down the snow. • Pack the grass down in the basket so the basket will hold more., Phrase(s): pack down
[for something] to settle down in a container. • The cereal has packed down in the box so that it seems that the box is only half full. • Everything was packed down carefully inside.
McGrawhill's American Idioms And Phrasal Verbs