a store of valuables, or the place that holds them: treasure, and the treasury or storehouse where treasure is kept
This one word slides between the valuables and the room that holds them, the way English does with "the king's treasure" and "the royal treasury." Sometimes it points to the wealth itself, the silver and gold and precious things piled up; sometimes to the strong-room, store-chamber, or granary built to keep them. Context, not a different word, tells you which is in view, and in many verses both are present at once.
The physical-place sense is concrete and institutional. The treasuries of the temple and the palace are real chambers, repeatedly emptied to pay off invaders or refilled by a faithful king. The grain store and the tithe storehouse work the same way: a designated place where something of value is gathered and kept in reserve.
The word also rises to a cosmic picture. The skies are God's storehouses, holding snow, hail, wind, the deep, and the rain that he opens up and dispenses at will. Here the stored thing is not money but weather and even sealed-up judgment, and the storeroom belongs to God alone. It is the same idea stretched to its largest scale: a reserve held back, under an owner's control, to be brought out when he chooses.