1. To flow or stream through some place or thing. Floodwater poured through the first floor of the building as the rain continued unabated. Cold air poured through a crack in the window. Sand is going to keep pouring through if we don't patch up that hole!
2. To cause a liquid or loose substance to flow or stream through some place or thing. In this usage, a noun or pronoun is be used between "pour" and "through." We poured the water through a mesh sieve to filter out pieces of debris. He began pouring sand through the opening of the tank to weight it down.
3. Of people, to throng and move together through some place or thing in great numbers and all at once. People poured through the streets to protest the government's controversial new legislation. Every single day, tens of thousands of tourists pour through the Grand Central Terminal in New York simply to take in its ornate splendor.
pour something through something
to cause something to flow through something, such as a filter. The chemist poured the mixture through the filter or opening. I can't get the syrup into the bottle without pouring it through a funnel.
pour through something
to flow freely through something. The water poured through the leak in the window frame. The rain poured through the hole in the roof.