Qabz is the Islamic concept of taking possession of something you've bought — either physically, or constructively (it's allocated to you and at your disposal). For ribawi items like gold, possession is required for the sale to be valid.
For gold to be bought in a halal way, you must take possession at the time of purchase. Many scholars accept constructive possession — gold allocated to you in a vault, fully yours — even if you never hold the physical bar.
In Pakistan: qabz is central to whether digital gold is Shariah-acceptable.
Example: fully-paid, allocated gold sitting in a vault under your name is constructive qabz; a "we'll deliver it to you later" gold deal lacks it.
Don't confuse it with: holding mere legal title with no real control over the asset.
Related terms: Riba · Ribawi item · Digital gold Where you'll meet this: Is digital gold halal?
Qabz (Possession)
Qabz is taking possession of something you've bought — physically or constructively — required for a valid sale of gold.