This is the 10572nd most frequent Russian word.
вместить
"To contain" or "to accommodate."
Here, 'вместить' is used in its literal sense to indicate the capacity of the box to contain a specific amount.
Эта коробка может вместить до десяти килограммов.
This box can hold up to ten kilograms.
'вместить' is employed to signify the act of adjusting the belongings to fit into the suitcase.
Ему удалось вместить все свои вещи в один чемодан.
He managed to fit all his belongings into one suitcase.
In this context, 'вместить' metaphorically means to condense or fit the speech within a time constraint.