To strengthen.
To accumulate, to pile up, to increase in stages.
To close up by building.
In solitaire card games, to place a card over another card of lower value. (e.g., place 5♦ over 4♣)
To erect; to construct.
To strengthen, especially by addition or augmentation.
To emphasize or review.
To encourage (a behavior or idea) through repeated stimulus.